Adaptive fuzzy controller

ABSTRACT

Fuzzy control systems and methods are disclosed. A method includes receiving a reference signal defining target values for a parameter that is controlled at an output of the plasma processing system and obtaining a measure of the parameter that is controlled at the output. A fuzzy controller provides a control signal to adjust at least one actuator based at least upon the reference signal and the measure of the controlled parameter. In addition, output membership functions of the fuzzy controller, input membership functions of the fuzzy controller, and a rule base of the fuzzy controller are adapted while controlling an output of a system based at least upon the based at least upon an estimated model parameter tensor, the reference signal and the measure of the controlled parameter, and the control signal.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to controller design. Inparticular, but not by way of limitation, the present disclosure relatesto systems, methods and apparatuses for designing an adaptivecontroller.

DESCRIPTION OF RELATED ART

Control systems have important applications in many technology areas,including plasma applications, semiconductor processing and othermaterials processing, robotics, vehicle control systems for automobiles,aircraft, and spacecraft, and other electronic, manufacturing, andindustrial systems. Semiconductor processing and other advancedmaterials processing rely on increasingly sophisticated plasmaprocesses. Such plasma processes, in turn, require increasinglysophisticated power systems and control systems, to subject inherentlyunstable and nonlinear plasmas to increasing precision and consistency.Such plasmas are used for processes such as plasma etch processes,plasma-enhanced chemical vapor deposition (CEPVD) processes,plasma-enhanced atomic layer deposition (PEALD) processes,plasma-assisted atomic-layer deposition (PA-ALD), RF sputteringdeposition, and other plasma processing applications.

In some plasma processing recipes, it is desirable to provide a pulsedwaveform having multiple states (or power levels) as exemplified by theillustrative waveform in FIG. 2 . Each recipe includes a number of pulsecycles (PC), number of pulses per pulse cycle, and a number of statesper pulse. Each state has a different target power level. In thisexample, two pulse cycles are shown, the first pulse cycle having sixpulses and each of those pulses having three states. The second pulsecycle has four pulses each having four states. Plasma processing systemscomprise many actuators to achieve a desired application of power suchas is shown in FIG. 2 . But in many instances, the actuators responddifferently to control signals because different actuators inherentlyhave different response times (e.g., some actuators respond much fasterthan other actuators) and/or the actuators operate in an asynchronousmanner. In the context of this disclosure, actuators may include,without limitation, higher-level constructs such as generators, matchnetworks, remote plasma sources, and bias supplies. In addition,actuators may include, without limitation, lower-level constructs suchas DC rail supplies, RF amplifiers, variable capacitors, and powersupplies within bias supplies and remote plasma source. In today'splasma processing systems, control (e.g., for precision and consistency)over the high-level actuators and low-level actuators is critical inview of the increasing speeds of the actuators and the ever-decreasingdimensions of the resultant processed-workpieces.

As an additional example, an RF generator for providing the pulsedwaveform in FIG. 2 may have actuators that include a DC section and apower amplifier where the DC section provides a rail voltage to thepower amplifier and the power amplifier provides the desired pulsedwaveform (e.g., FIG. 2 ) using the rail voltage. The power amplifier isrelatively fast (e.g., ˜250 ns) compared to changes in the targetvoltage, but the DC section or the rail, is relatively slow (e.g., ˜1ms). As a consequence, existing control systems tend to hold the rail ata high level for much of a pulse cycle (e.g., at a highest level neededfor a given pulse cycle). However, this can lead to overheating ofcomponents and premature system failure and maintenance needs as well asinefficiency since the rail is often far above the level needed at anymoment in time (i.e., for a given state within a pulse of a pulsecycle).

Current adaptive controllers do not have inherent stability or theguarantee that they will converge. Further, existing adaptivecontrollers utilize transfer functions, and are thus difficult to scaleto arbitrary waveforms and coupled inputs and outputs (MIMO). They alsotend to be limited to a single control law and thus luck adaptability tovarious situations that may arise even within a given recipe. Further,existing adaptive engines struggle with unstable systems as well asunbounded computed control values as well as modeling uncertainties andinput and output bounded disturbances that can be arbitrary. Lastly,they struggle with handling different modeling/parameterizations of theprocess to be controlled.

SUMMARY OF THE DISCLOSURE

Some aspects may be characterized as a control system including a userinterface configured to receive a reference signal defining targetvalues for a controlled parameter that is provided to a controlledoutput of the system; at least one sensor to obtain a measure of thecontrolled parameter that is controlled at the controlled output; and anestimation law module configured to produce an estimated model parametertensor, Θ. A fuzzy controller is configured to provide a control signalto adjust at least one actuator based at least upon the reference signaland the measure of the controlled parameter and a dynamic modificationmodule configured, while controlling the controlled parameter, based atleast upon the reference signal, an estimate of the controlledparameter, the measure of the controlled parameter, and the controlsignal to: adapt output membership functions of the fuzzy controller;adapt input membership functions of the fuzzy controller; and adapt arule base of the fuzzy controller.

Another aspect may be characterized as a method for controlling a plasmaprocessing system including receiving a reference signal defining targetvalues for a parameter that is controlled at an output of the plasmaprocessing system; obtaining a measure of the parameter that iscontrolled at the output; and producing an estimated model parametertensor, Θ. A fuzzy controller to provide a control signal to adjust atleast one actuator based at least upon the reference signal and themeasure of the controlled parameter; adapting output membershipfunctions of the fuzzy controller, input membership functions of thefuzzy controller, and a rule base of the fuzzy controller whilecontrolling the controlled parameter, based at least upon the based atleast upon the estimated model parameter tensor, Θ, the referencesignal, an estimate of the controlled parameter, the measure of thecontrolled parameter, and the control signal.

Yet another aspect may be characterized as a non-transitory mediumencoded with instructions that are executable by a processor and/or usedto program a field programmable gate array. The instructions includinginstructions to receive a reference signal defining target values for aparameter that is controlled at an output of a plasma processing system;obtain a measure of the parameter that is controlled at the output; andproduce an estimated model parameter tensor, Θ. The instructions includeinstructions to control a fuzzy controller to provide a control signalto adjust at least one actuator based at least upon the reference signaland the measure of the controlled parameter. In addition, theinstructions include instructions to adapt output membership functionsof the fuzzy controller, input membership functions of the fuzzycontroller, and a rule base of the fuzzy controller while controllingthe controlled parameter, based at least upon the based at least uponthe estimated model parameter tensor, Θ, the reference signal, anestimate of the controlled parameter, the measure of the controlledparameter, and the control signal.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects and advantages and a more complete understanding of thepresent disclosure are apparent and more readily appreciated byreferring to the following detailed description and to the appendedclaims when taken in conjunction with the accompanying drawings:

FIG. 1 illustrates a plasma processing system;

FIG. 2 illustrates a pulse waveform for the system of FIG. 1 ;

FIG. 3 illustrates a method of controlling the system of FIG. 1 ;

FIG. 4 Illustrates a plasma processing system having an adaptive engineconfigured to control one or more actuators;

FIG. 5A shows an embodiment of an adaptive engine such as the one shownin FIG. 4 ;

FIG. 5B shows an embodiment of an adaptive engine where an estimationportion of the nonlinear model is processed in the estimation lawmodules;

FIG. 5C shows an embodiment of an adaptive engine where multipleestimation law modules provide outputs to a single control law module;

FIG. 6 illustrates an alternative adaptive engine that splits controlsamples, and certain aspects of the nonlinear model, into frames;

FIG. 7 illustrates a method of adaptive control;

FIG. 8A illustrates further detail of certain embodiments of theestimation law modules and the corresponding estimation laws;

FIG. 8B illustrates further detail of certain embodiments of theestimation law modules and the corresponding estimation laws;

FIG. 9 illustrates a method of operating the herein disclosed adaptiveengine having a bifurcated nonlinear model;

FIG. 10A shows an embodiment of an adaptive engine focusing on detailsof a Lyapunov control law module or sub-engine;

FIG. 10B shows a variation on FIG. 10A, where a derivative of theestimated model parameter tensor is also calculated and used;

FIG. 11A depicts an example of an adaptive engine implementing a TARCcontrol law sub-engine, according to various aspects of the disclosure;

FIG. 11B illustrates a detailed view of an Adaptive Inverse Laws (AIL)control law module of the TARC control law sub-engine in FIG. 11A,according to various aspects of the disclosure;

FIG. 11C illustrates an alternate view of an Adaptive Inverse Laws (AIL)control law module of the TARC control law sub-engine in FIG. 11A,according to various aspects of the disclosure;

FIG. 12 illustrates an example of a method for controlling a nonlinearsystem using the TAC control law sub-engine, according to variousaspects of the disclosure;

FIG. 13A illustrates a pre-computation block of the ATML module of theTARC control law sub-engine, in accordance with one or moreimplementations;

FIG. 13B illustrates a block diagram of the Eigen control laws module ofthe TARC control law sub-engine, in accordance with one or moreimplementations;

FIG. 13C illustrates a block diagram showing the penalty control lawsmodule of the TARC control law sub-engine, in accordance with one ormore implementations;

FIG. 14 depicts a block diagram of an adaptive engine showing thedetails of the TFPA control law sub-engine, in accordance with one ormore implementations;

FIG. 15 illustrates an example of a method for controlling a nonlinearsystem using the TFPA control law sub-engine, in accordance with one ormore implementations;

FIG. 16 illustrates a block diagram of an adaptive PID control system,in accordance with one or more implementations;

FIG. 17A illustrates an example of a method for controlling a nonlinearsystem using the adaptive PID control system in FIG. 16 , in accordancewith one or more implementations;

FIG. 17B illustrates another example of a method for controlling anonlinear system using the adaptive PID control system in FIG. 16 , inaccordance with one or more implementations;

FIG. 18 illustrates a block diagram of an adaptive engine implementingan adaptive PID control law sub-engine, in accordance with one or moreimplementations;

FIG. 19 illustrates a block diagram of an adaptive engine showing thedetails of the CTOE control law module in FIG. 18 , in accordance withone or more implementations;

FIG. 20 depicts a block diagram showing an example of how a control lawis implemented in the CTOE control law module in FIG. 18 , according tovarious aspects of the disclosure;

FIG. 21 depicts a block diagram of an adaptive engine showing a detailedview of the OETC control law module in FIG. 18 , according to variousaspects of the disclosure;

FIG. 22 illustrates an example of a method 2200 for controlling anonlinear system using an ATIMC control law sub-engine, in accordancewith one or more implementations;

FIG. 23 illustrates an example of an adaptive engine implementing anATIMC control law sub-engine, in accordance with one or moreimplementations;

FIG. 24 illustrates another example of an adaptive engine implementingan ATIMC control law sub-engine, in accordance with one or moreimplementations;

FIG. 25 illustrates a detailed view of a first mapping module of theATIMC control law sub-engine in FIG. 24 , in accordance with one or moreimplementations;

FIG. 26 illustrates a detailed view of a first mechanism implemented inthe ATIMC control law sub-engine in FIG. 24 , in accordance with one ormore implementations;

FIG. 27 illustrates a detailed view of a second mapping module of theATIMC control law sub-engine in FIG. 24 , in accordance with one or moreimplementations;

FIG. 28 illustrates a detailed view of a third mapping module of theATIMC control law sub-engine in FIG. 24 , in accordance with one or moreimplementations;

FIG. 29 illustrates a detailed view of a second mechanism implemented inthe ATIMC control law sub-engine in FIG. 24 , in accordance with one ormore implementations;

FIG. 30 illustrates a detailed view of a fourth mapping module of theATIMC control law sub-engine in FIG. 24 , in accordance with one or moreimplementations;

FIG. 31 is a block diagram depicting an adaptive fuzzy controller;

FIG. 32 is a flowchart depicting a method for controlling a plasmaprocessing system with the adaptive fuzzy controller depicted in FIG. 31;

FIG. 33 is a graphical representation of generic membership functionsthat may be used in the adaptive fuzzy controller depicted in FIG. 31 ;

FIG. 34 is a graphical representation of a specific example ofmembership functions that may be used in the adaptive fuzzy controllerdepicted in FIG. 31 ;

FIG. 35 is a graphical representation of an example of fuzzification ofa rule;

FIG. 36 is a graphical representation of an example of fuzzification ofanother rule;

FIG. 37 is a graphical representation of an output membership functionthat results from the fuzzy rule depicted in FIG. 35 ;

FIG. 38 is a graphical representation of an output membership functionthat results from the fuzzy rule depicted in FIG. 36 ;

FIG. 39 is a block diagram depicting an example adaptive fuzzycontroller that may be used to realize the adaptive fuzzy controllershown in FIG. 31 ;

FIG. 40 is a block diagram depicting an example of a control-to-estimatemapping module that may be used to realize the control-to-estimatemapping module depicted in FIG. 39 ;

FIG. 41 is a block diagram depicting an example correction module thatmay be used to realize the correction module depicted in FIG. 39 ;

FIG. 42 is a block diagram depicting an example zooming and shiftingmodule that may be used to realize the zooming and shifting moduledepicted in FIG. 39 ;

FIG. 43 shows a plot illustrating the concept of the bifurcated modelfor the estimation portion;

FIG. 44A shows a graph of the desired reference signal in FIG. 45 ,where a control parameter is closer to the desired reference signalduring pulse 2;

FIG. 44B shows a graph of the desired reference signal of FIG. 45 ,where the controlled parameter achieves the controlled output;

FIG. 44C shows a graph of the desired reference signal of FIG. 45 ,where the controlled parameter achieving the controlled output;

FIG. 45 shows an example of an actuator output that is produced inresponse to a desired reference signal where the desired referencesignal;

FIG. 46 shows an illustrative example of operation of an adaptive engineaccording to embodiments of this disclosure;

FIG. 47 illustrates a method of operating a sub-engine such as theLyapunov sub-engine

FIG. 48 shows a block diagram depicting physical components that may beutilized to realize the adaptive engine according to an exemplaryembodiment;

FIG. 49 illustrates a method of adaptive control where mappings of thecontrol laws are empirically derived;

FIG. 50 shows another alternative where the mapping function alsodetermines the estimated system output, y_(est_se);

FIG. 51 shows a mapping function as used during a boot up phase of analternative adaptive engine;

FIG. 52 shows a mapping function as used during an adaptation phase ofan alternative adaptive engine; and

FIG. 53 shows a mapping function as used during an adaptation phase ofan alternative adaptive engine.

DETAILED DESCRIPTION

A tensor is a multi-dimensional array with a uniform type. In otherwords, a tensor is an algebraic object that describes a multilinearrelationship between sets of algebraic objects related to a vectorspace. Objects that tensors may map between include vectors and scalars,and even other tensors. An example of a zero-order tensor is a fixedpower setpoint, while a first-order tensor is a vector, such as phasorrepresenting the phase shift between two waveforms (e.g., voltage andcurrent). A second-order tensors is a matrix, where two matrices mightbe used to represent estimated future values of reflected power and loadimpedance at two future times, and where multiplying those matricestogether may be used as a simplified mathematical operation to predict atrajectory of reflected power and load impedance into the future. As canbe seen, tensors provide a way to simplify complex sets of data andmathematical operations, which not only helps simplify complex MIMOapplications in this disclosure, but also allows for parallel processingand more efficient use of limited processing resources for predictingnonlinear dynamics in power and plasma systems.

The index “k” will be used to specify an iteration, such that a timingof a generalized variable can be described with the addition of k. Forinstance, the control for a previous iteration may be denotedu_(out_k−1) and u_(out_k) for a current iteration. This exemplary use ofiteration index k can be used across all variables to provide claritywhen a discussion of multiple iterations of the same variables isneeded, but otherwise, generalized versions of variables will not usethe iteration index k.

For the purposes of this disclosure, an estimation error, ê, and anestimated system output error, ê_(out), can each be replaced by a costfunction, J or J_(out), respectively. Accordingly, this disclosure willoften only discuss an estimation error e and a system output errorê_(out), and these references should be understood to also include costfunction variations of these errors. It should be noted that the hatsymbol over the “e” represents an estimation. An actual system error,ê_(out), will also be discussed and this should not be confused with theestimated system error, ê_(out).

Traditional control systems often look at an error, e, between thereference signal, r, and the measurements of delivered power, y_(meas),and produce a control, u_(out), proportional to the error, e. However,such controls can suffer when presented with nonlinearities and unknowndisturbances, among other challenges. To address nonlinear systems,nonlinear systems with uncertainty, linear systems with uncertainty, andsystems with unknown variations in plant parameters, adaptive controlshave been developed. The basic aim of adaptive control is to maintain aconsistent performance of a system in the presence of uncertainty orunknown variation in plant parameters, but with changes in thecontroller parameters, adapting to the changes in the performance of thecontrol system. Hence, there is an adaptation in the controller settingsubject to the performance of the closed-loop system. How the controllerparameters change is decided by the adaptive laws, which are oftendesigned based on the stability analysis of the adaptive control system.

A number of design methods have been developed for adaptive control.Model Reference Adaptive Control (MRAC) consists of a reference modelwhich produces the desired output, and the difference between the plantoutput and the reference output is then used to adjust the controlparameters and the control input directly. MRAC is often incontinuous-time domain, and for deterministic plants. Self-TuningControl (STC) estimates system parameters and then computes the controlinput from the estimated parameters. STC is often in discrete-time andfor stochastic plants. Furthermore, STC often has a separateidentification procedure for estimation of the system parameters, and isreferred to as indirect adaptive control, while MRAC adapts to thechanges in the controller parameters, and is referred to as directadaptive control. However, the development of a general robust adaptivecontroller remains at present an open problem. Martin Guay et al. Robustand Adaptive Model Predictive Control of Nonlinear Systems, Control,Robotics and Sensors Series 83, page 76.

This disclosure presents an updated adaptive engine that can combineinfluences from multiple estimation laws in a manner that addressescertain challenges of an input waveform and/or system to be controlled,such as nonlinear systems, nonlinear systems with uncertainty, linearsystems with uncertainty, and systems with unknown variations in plantparameters. Further, changes to the blending of these influences can beadjusted in real-time to cope with the often nearly instant changes seenin nonlinear systems.

Referring to FIG. 4 shown is a block diagram depicting aspects of apredictive and tensorial control approach that may be utilized inconnection within a plasma processing system 400 (though systems otherthan a plasma load can also be controlled by the actuator(s) 408). Shownin FIG. 4 is an adaptive engine 420, which is coupled to a userinterface 108, one or more actuator(s) 408, and sensors 410. Alsocoupled to the adaptive engine 420 is a delay/amplitude estimator 404.As discussed further herein, the delay/amplitude estimator 404 may befurther separated into functional subcomponents or consolidated, and thefunctionality of the delay/amplitude estimator 404 may be carried out inpipelining-type approaches or may be serially effectuated, which one ofordinary skill in the art, in view of this disclosure, will understand.

While referring to FIG. 4 , simultaneous reference is made to FIG. 3 ,which is a flow chart depicting steps that may be traversed inconnection with embodiments of the disclosure herein. The user interface108 is configured to receive (Block 302) a reference signal, r, definingtarget values (or reference signals) for one or more controlledparameters that is applied to one or more controlled outputs within thesystem. In other words, the reference signal, r, can be an n-dimensionalentity where n>0. For instance, a one-dimensional reference signal, r,is more typically referred to as a reference signal. In someembodiments, r, can also refer to a series of setpoints or a setpointstream. The target values may represent multi-level pulsed waveforms orany arbitrary waveform. As shown, the controlled outputs within thesystem 400 may include a load output 430, which is a node that iscoupled to the nonlinear and/or chaotic load 104, and/or the controlledoutputs may include one or more actuator(s) outputs 432. In other words,the adaptive engine 420 may be used to control one or more controlledparameters at the load output 430 that may include power-relatedparameters including, for example and without limitation, DC power,forward power, reflected power, reflection coefficient, frequency, andcurrent. In addition, the adaptive engine 420 may be used to controlcontrolled parameters that are applied at the actuator(s) outputs 432.The controlled parameters applied to actuator(s) outputs 432 may includethe power-related parameters listed above (in connection with the output430 (load output)) and control-related parameters such as aphase-control signal, frequency control signal, and voltage-controlsignals. In addition, one or more particular actuator outputs 432 mayfeed as an input 434 to one or more other actuators 408. The actuatoroutputs 432 need not have similar response times, for instance, but notlimited to, where one actuator drives a fast power source and a secondactuator drives a slower rail voltage.

As shown, at least one sensor 410 is configured to obtain a measure(Block 304) of the parameters such as the power-related parameters andthe control-related parameters listed above. The at least one sensor 410may include, for example and without limitation, directional couplers,VI sensors, current transducers, and simple voltage sensors. Those ofordinary skill in the art will appreciate that the signals from the atleast one sensor 410 may be sampled and converted into digital formatfor use by the adaptive engine 420.

A delay/amplitude estimator 404 is configured to calculate a delay(Block 306) between the target values of the reference signal 405 andcorresponding actual parameter values achieved at the controlled output(i.e., measured system outputs). The delay/amplitude estimator 404 isalso configured to provide, based upon the delay, a time-shiftedamplitude error 452 indicative of an error between the target values andthe actual parameter values (Block 308). According to one aspect, theadaptive engine 420 is beneficially configured to adjust at least one ofthe actuators 408 (based upon the delay 450 (at Block 306) and thetime-shifted amplitude error 452 (at Block 308)) in advance of when anactual parameter value is needed (at an actuator output of the at leastone actuator 408) while maintaining the controlled parameter at thecontrolled output within a threshold range (Block 301).

Referring briefly to FIG. 45 for example, shown is an example of anactuator output 4534 (e.g., rail voltage, V_(rail)) that is produced(using the adaptive engine 420) in response to a desired referencesignal where the desired reference signal comprises three pulses andeach pulse includes three target values (desired at the controlledoutput for a controlled parameter): state 1, state 2, and state 3. Eachstate of the desired reference signal corresponds to a target value of acontrolled parameter at the output 430 (e.g., forward power). As shown,during pulse 1, the actuator output 4534 is adjusted, at t₁, in veryclose connection with a time when it is needed—at the change in thereference signal from state 1 to state 2. But during pulse 2, theactuator output is adjusted, at t₂, in advance of when the actuatoroutput 4534 needs to be increased to produce the target value of state 2at the output 430. As a consequence, the controlled parameter (e.g.,forward power) at the controlled output (e.g., load output 430) willreach the desired reference signal faster than prior controlmethodologies that attempt to minimize energy dissipation (usingactuator output 4562), and faster than prior methods that attempt tomaximize a speed of response (using actuator output 4564). Thepredictive functionality of the delay/amplitude estimator 404 enablesthe adaptive engine 420 to adjust the actuator (e.g., rail voltage) inadvance of when it is needed by predicting the effects of adjusting theactuator in advance of when it is needed so that adverse consequences(e.g., reference signal errors or over voltage conditions) are avoided.

Referring to FIGS. 44A, 44B, 44C for example, shown are three graphs,and each of the three graphs depicts the same desired reference signalthat is shown in FIG. 45 with the same three desired states per pulse.FIG. 44A depicts the controlled parameter actually achieved at thecontrolled output using the predictively produced actuator output 4534;FIG. 44B depicts the controlled parameter actually achieved at thecontrolled output using the actuator output 4562; and FIG. 44C depictsthe controlled parameter actually achieved at the controlled outputusing the actuator output 4564. As shown in FIG. 44A, the controlledparameter is closer to the desired reference signal during pulse 2 whenthe controlled actuator is controlled (in advance of when it is needed)to produce the actuator output 4534 as compared to both the controlledparameter values in FIGS. 44B and 44C.

As discussed further herein, the delay/amplitude estimator 404 may beimplemented with different levels of complexity, but in general, thedelay/amplitude estimator 404 is configured to detect a delay 450between a desired reference signal (from the user interface 108) and thetime when the actual output of one or more actuators 408 reaches thereference signal. As discussed further herein, the reference may be atime varying streaming reference signal (e.g., a reference signal thatmirrors the pulses and states in FIG. 2 ) and, as discussed furtherherein, the delay 450 may be determined based upon a cross correlationbetween the streaming reference signal and the actual time-varyingoutput of one or more actuators 408 in the system. Moreover, asdiscussed further herein, the delay 450 may be a simple delay (e.g.,between a reference signal and an output when the reference signal isachieved) or the delay 450 based on several constituent delay componentsincluding delays within an actuator 408 and/or external delays outsideof the actuator 408. With knowledge of the delay 450, thedelay/amplitude estimator 404 may determine a time-shifted amplitudeerror 452, which is generally indicative of an error value based upon adifference between the streaming reference signal and the output that isdetermined after the streaming input waveform and an output waveform arerelatively time-shifted (based upon the delay 450) so that, on anongoing basis, a portion of the output waveform is aligned with thecorresponding portion of the reference signal that effectuated theportion of the output waveform. Once the output waveform is aligned withthe streaming reference signal, an error value, represented as thetime-shifted amplitude error 452, may be calculated.

The adaptive engine 420 utilizes the delay 450 and the time-shiftedamplitude error 452 to predict how the control signal(s) and or actuatoroutput(s) will react to potential control signal changes—in advance ofactually changing the control signals. By predicting how the actuatoroutputs will be affected (in advance of actually changing the controlsignals to the actuators 408) the adaptive engine 420 may adjust thecontrol signals to achieve desired results. For example, based uponpredicted-control-signal outputs, the adaptive engine 420 may adjust thecontrol outputs to: reduce a time it takes to achieve a desired outputof the actuator(s); to reduce energy dissipation; to prevent damagingover voltage and/or over current conditions; and/or to achieve anydesired balance between speed, accuracy, and energy.

It should be recognized that FIG. 4 is a simplified depiction of whatmay be implemented on a tensorial level with many reference signals,many control signals, and many actuators 408. It should also berecognized that the actuators may be higher-level actuators (such asgenerators, match networks, RF sources, and bias supplies) andlower-level constructs within the higher-level actuators. For example, aDC section and the power amplifier are examples of actuators within agenerator that may be controlled (as discussed further herein as anon-limiting example). By way of further example, the voltage of the DCsection may be controlled, and a frequency of the power amplifier may becontrolled using the adaptive engine 420.

As another example, the match network 116 is an example of an actuator408, which also comprises actuators such as variable capacitors that maybe controlled using of the delay estimation and predictive controlaspects of the delay/amplitude estimator 404 and the adaptive engine420, respectively. It is contemplated, for example, that variablecapacitors of the match network 116 may be controlled in isolation(e.g., based upon reflected power) or in connection with a variablefrequency drive of the generator 102 using the of the delay/amplitudeestimator 404 and adaptive engine 420. As a further example, the biassupply 120 is an actuator 408, and the bias supply 120 comprisesactuators 408 such as a power supply (e.g., to establish a rail voltage)and a switching-section to establish timing of a periodic asymmetricalvoltage waveform. These actuators 408 of a bias supply may be controlled(using the estimation and prediction techniques of the delay/amplitudeestimator 404 and adaptive engine, respectively) to control the biassupply 120. Or other actuators of the bias supply may be controlled inview of other actuators such as the RF source 118 and/or generator 102to synchronize the bias supply 120, the RF source 118, and/or thegenerator 102 to achieve desired plasma processing recipe results and/orto prevent undesired plasma modulation (e.g., due to intermodulationfrequencies).

In more general terms, various aspects of the delay estimation andpredictive control, and/or adaptive control, may enable direct,unhindered (or without response delay) control of a parallelmulti-actuator or multi-knob nonlinear control system (such as theplasma processing systems 100, 400). A controller utilizing the delayestimation, prediction, and/or adaptation, may enable moreresponsiveness (e.g., maximize dynamic range in real time) andadaptability of a parallel multi-actuator nonlinear and/or chaoticcontrol system. Moreover, the delay estimation and predictive aspects,as well as the adaptation aspects of this disclosure may enable improvedcontrols (e.g., to maximize the speed of the response and achieve theshortest response time to reach a desired reference signal value, whilealso enabling stability and robustness) of a parallel multi-actuatornonlinear and/or chaotic control system. The delay estimation andpredictive aspects and adaptation aspects may also enable all of theabove functions and advantages to be achieved even when some of theactuators of the control system are arbitrarily slower than otheractuators of the control system.

Another aspect of the delay estimation and predictive and/or adaptivecontrol of this disclosure may enable all of the above functions andadvantages to be achieved even when multi-level pulsing with a number ofstates (going up to an arbitrary number) is desired, and/or arbitrarywaveform tracking is required on a nonlinear and/or chaotic dynamicload. Yet another aspect may also enable all of the above functions andadvantages to be achieved even while minimizing the control energyexpended in the system. As discussed further herein, the delayestimation and predictive control aspects and/or adaptation aspects mayalso enable all of the above functions and advantages to be achievedwhile protecting hardware from faults relating to high dissipation, highcurrents, and/or high voltages. Moreover, another aspect of the delayestimation and predictive control and/or adaptation methodologies mayalso enable all of the above functions and advantages to be achievedeven while making sure all the different actuators work cooperativelytogether such that no actuator is controlling itself in a manner thathinders, impedes, or interferes with the control of the other actuatorsin such a way that would cause the system response to become slower, orrequire more energy to be achieved from any or all of the otheractuators.

Adaptive Engine

At a high level, the adaptive engine splits, or bifurcates, adaptivecontrol for highly nonlinear and/or chaotic systems, such as powersupplies for plasma processing. The adaptive engine starts with anonlinear model of one or more actuators and/or a power systemcontrolled by the one or more actuators, and defines two outputs of thisnonlinear model: one for control, u_(se), and one for an estimatedsystem output, y_(est_se), based on that control, u_(se). Two parts ofthe nonlinear model that achieve these outputs can be referred to as acontrol portion and an estimation portion. There are different ways ofexpressing these two portions as will be discussed later, but for thepurposes of illustration, one form of the control and estimationportions of the nonlinear model can be written as:

u _(se)=Θ·Ø  (Control Portion of Nonlinear Model)

y _(est_se) =W _(m) {u _(se)}  (Estimation Portion of Nonlinear Model)

The control portion is a function of estimated parameter values for thenonlinear model, referred to as an estimated model parameter tensor, Θ,as well as an input regressor, Ø, that can include elements such as areference waveform, r. As seen, the estimation portion is dependent onthe answer to the control portion as well as a time-varying linearsystem, W_(m). The time-varying linear system, W_(m), is composed of thefollowing system of equations:

$\left\{ {\begin{matrix}{\overset{.}{x} = {{Ax} + {Bu}_{se}}} \\{y_{{est}\_{se}} = {Cx}}\end{matrix}\left( {{{Time} - {Varying}{Linear}{System}},W_{m}} \right)} \right.$

Where x is an internal state and where A, B, and C are matrices whosestructure defines characteristics of the nonlinear model, and whoseelements can include 1, 0, Θ, and fixed coefficients. In some cases, thestructure may include changing an element from Θ to a fixed coefficient,where it is known that adaptation of this element of the estimated modelparameter tensor, Θ, is not needed or doesn't provide significantimprovement. One sees that with knowledge of the A, B, and C matrices,and a value for the possible control signal, u_(se), the system can besolved for the estimated system output, y_(est_se). More specifically:

{dot over (y)}=Ay+Bu _(se)

So, W_(m){u_(se)} leads to y_(est_se) by integrating {dot over (y)}.

Although C can vary, in some embodiments C can be the identity matrixfor improved performance. At the start of each frame, x can take thelast value of x from the previous frame.

This disclosure improves on existing nonlinear modeling techniques bybifurcating the time-varying linear system, W_(m), into a linear and anonlinear portion. The nonlinear portion is unknown, and thisdisclosure's adaptive control seeks to minimize this unknown nonlinearportion via adaptation of the linear portion. Adaptation of the linearportion can also be bifurcated via the use of frames. The referencesignal, r, can be split into frames, each potentially having a differentnumber of control samples or iterations, such that each frame allows atime-varying linear approximation of the nonlinear system behaviorresulting from the reference signal, r, for that frame. Thus, eachframe's length is selected so as to optimize the linear approximation.The time-varying linear approximation, or W_(m), has a structure asnoted above, that is selected for each frame. This structure, or thestructure of the A, B, and C matrices, determines large scale changes orshapes of the model. Yet, the time-varying linear system, W_(m), is alsoa function of the estimated model parameter tensor, Θ, which ismodified, or adapted, at each control sample or iteration of theadaptive engine. So, while the structure of the time-varying linearsystem, W_(m), remains constant through a frame, Θ changes, and thusW_(m) changes. These changes resulting from adaptation of Θ tend to besmall compared to the changes resulting from the structure changing.Thus, adaptation of the estimation model parameter tensor, Θ, allowssmall nonlinear variations in system behavior to be modeled andprocessed in real-time, while larger variations in system behavior aremodeled by changes in the W_(m) structure, which change every frame.Because the structure only changes frame-by-frame, these values can bepre-processed and can use a processing resource with less power than oneneeded to process the estimated model parameter tensor, Θ, adaptation.For instance, the structure of the time-varying linear system, W_(m),can be processed on a CPU, while the adaptation of the estimated modelparameter tensor, Θ, can be processed in real-time on an FPGA.

At the start of each frame, the estimated model parameter tensor, Θ,begins with a set of initial conditions, and thus, the time-varyinglinear system, W_(m), and hence the nonlinear model, may form a veryrough approximation of the nonlinear system behavior (i.e., outputs ofthe model may see some error from actual system behavior). However, theadaptive engine guesses and tests values for the estimated parametertensor, Θ, or adapts them, during a plurality of control samples oriterations, and as this occurs, the time-varying linear system, W_(m),becomes a better and better approximation of the nonlinear systembehavior until the error (or the unknown nonlinear portion of W_(m))fall below a threshold at which W_(m) is considered to have convergedand no further adaptation is needed (i.e., no further changes to Θ areperformed). Said another way, the adaptive engine pre-processes adifferent nonlinear approximation (dependent on Θ) of the system'snonlinear behavior for each frame, and then within each frame, theadaptive engine adjusts the nonlinear approximation via adaptation ofthe estimated model parameter tensor, Θ, to bring the linearapproximation into even closer alignment with the system's nonlinearbehavior. This bifurcation of calculating the linear approximation (thestructure of the A, B, and C matrices) on a frame-by-frame basis, andreal-time adaptation of the estimated model parameter tensor, Θ, of thetime-varying linear approximation, allows different processing resourcesto be applied to their best functions: slower resources like a CPU canprocess the structure of the time-varying linear system at a slowerpace, and faster resources like an FPGA can process adaptation ormodification of the time-varying linear system (via 0) within each frameat a faster pace. This bifurcation allows faster and more robustconvergence on nonlinear behavior than has been possible in existingadaptive controllers.

FIG. 43 shows a plot illustrating the concept of the bifurcated modelfor the estimation portion. In this plot, the model output is power, andthis can be estimated using an estimation portion of the model, whichdepends on W_(m) and u_(se), though other outputs can also be handled bythe models of this disclosure. The time-varying linear system, W_(m),can be bifurcated into a linear (dashed lines) and a nonlinear part(solid lines). The linear part can be referred to asW_(m_linear)(u_(se), Θ), and depends on the estimated model parametertensor, Θ, and the possible control signal, u_(se), both of which varyper control sample or iteration, and where the structure of this linearpart changes with each new frame. The unknown nonlinear part can bereferred to as W_(m_non-linear)(k), and oscillates with every controlsample or iteration due to adaptation of the estimated model parametertensor, Θ, but whose oscillation becomes smaller as the linear portionis adapted and the nonlinear model becomes a better and betterapproximation of the actual nonlinear system behavior. As the adaptationimproves, the unknown nonlinear portion W_(m_non-linear)(k) of thetime-varying linear system, W_(m), becomes small enough to be ignored.In other words, while the structure of the linear portion does notchange within a frame, its overall influence on the model output doeschange as the adaptation of Θ brings the linear portion into betteralignment with the system's nonlinear behavior. Thus, at the start ofeach frame, the nonlinear portion is likely large, but as the linearportion is adapted (as the estimated model parameter tensor, Θ, isadapted), the linear portion, W_(m_linear)(u_(se), Θ), becomes a betterapproximation of actual behavior and the unknown nonlinear portion orerror is reduced until it falls below a threshold and the adaption isconsidered complete for that frame (i.e., convergence). In other words,at some point in each frame the adaptive engine adapts the linearportion W_(m_linear)(u_(se), Θ) of the time-varying linear system,W_(m), to be a very good approximation of W_(m), and the unknownnonlinear portion W_(m_non-linear)(k) is small enough to ignore. Saidanother way, the net effect of this structural change fromframe-to-frame and the adaptation of the linear portion within eachframe, allows the overall model (W_(m){u_(se),Θ}) to quickly converge onnonlinear system behavior since the structure of each frame can bepre-computed (e.g., on a CPU) or empirically derived, and thus only theadaption of the linear portion W_(m_linear)(u_(se), Θ) is performed withreal-time processing resources (e.g., FPGA).

FIG. 9 illustrates a method of operating the herein disclosed adaptiveengine having a bifurcated nonlinear model. The method 900 can includeproviding a system model (or “nonlinear model”) with a control portion,for generating possible control signals, u_(se), and an estimationportion for estimating estimated system outputs, y_(est_se) (Block 902).The time-varying linear system, W_(m), can be bifurcated or split into asum of a linear and a nonlinear portion and the control timeline can besplit into frames of differing lengths (or number of control samples oradaptation iterations) (Block 904) with some processing of the nonlinearmodel occurring on a CPU or other slower resource and real-time aspectsof the nonlinear model occurring on an FPGA or other faster resource. Acurrent frame can be supplied with a structure of the time-varyinglinear system, W_(m) (Block 906). As noted relative to FIG. 43 , thenonlinear portion of the time-varying linear system, W_(m), iseffectively an unknown error and thus not used or considered in theprocessing (other than in attempt to minimize this error). For thisreason, the terms time-varying linear system, W_(m), and the linearportion thereof, W_(m_linear)(u_(se), Θ), will be used interchangeably,with this simplification becoming more accurate as convergence occurs ineach frame. The structure of the time-varying linear system, W_(m), canbe pre-processed, for instance on a CPU, though it can also be accessedfrom an empirically-derived lookup table. The structure of thetime-varying linear system, W_(m), remains constant through the currentframe. Yet, since the time-varying linear system, W_(m), is alsodependent on the estimated model parameter tensor, Θ, the estimationportion of the nonlinear model adapts within a frame as Θ changes (asthe adaptive engine modifies Θ to minimize an error relative to measuredsystem behavior) (Block 908). This can involve calculating an estimationerror, ê, or cost function, J, based on two or more of (1) measuredsystem outputs, y_(meas), from a previous iteration, (2) estimatedsystem outputs, y_(est_se), from a previous iteration, and (3) referencesignal, r (Block 912). Adaption can then involve applying an estimationlaw to at least the reference signal, r, and the estimation error, ê, orcost function, J, to estimate an estimated model parameter tensor, Θ(Block 914). This adaption (Blocks 912, 914, and 918 and Decision 916)continues through the entirety of the frame, and in turn, W_(m), isadapted throughout the frame (or until convergence is achieved). Once aframe is complete (Decision 916=Yes), the method 900 selects a nextframe (Block 910), and a new structure of the time-varying linearsystem, W_(m), is provided into the model (Block 906), and adaptation ofthe estimated model parameter tensor, Θ, (Block 908) is carried outthrough this next frame until convergence. As noted earlier, thestructure of the time-varying linear system, W_(m), can include thestructure of the A, B, and C matrices that are part of the system ofequations making up W_(m). This simplified overview of the bifurcatednonlinear model operation will be further detailed with reference to thevarious figures that follow.

FIG. 5 shows an embodiment of an adaptive engine such as the one shownin FIG. 4 . The adaptive engine 500 is configured to provide an adaptedcontrol signal, u_(out), to one or more actuators (e.g., actuator(s) 408in FIG. 4 ), where the adapted control signal, u_(out), is configured toconverge on a target parameter more quickly, such as a reference signalwaveform, than is possible via known controllers. Although the adaptedcontrol signal, u_(out), (hereinafter “control signal” or “control”) mayhave multiple components in a MIMO system (i.e., may be a tensor or maybe tensorized), for simplicity it will be referenced in the singularthroughout this disclosure, and those of skill in the art will be ableto apply the adapted control signal, u_(out), to situations where one ormore control signals are implemented (i.e., to a tensorial adaptedcontrol signs, u_(out)). Further, where the system being controlledpresents nonlinearities and instabilities, such as found in a plasmacontrol system, the adaptive engine 500 is able to adjust the amount andmeans of adaptation to avoid instability, even for instance, at the costof slower convergence. This will be referred to as “adaptation gain”.

At the same time, different ones, numbers, and combinations of controllaws can be applied to optimize the control signal, u_(out), fordifferent signals and situations. Similarly, different estimation lawscan be used to estimate parameters of a nonlinear model of the actuatorsand/or system controlled by the actuators. The nonlinear model can be afunction of an input regressor, including values such as a referencesignal, and can also be a function of the estimated model parameters.Both the input regressor and the estimated model parameters are updatedfor each iteration, such that the nonlinear model is “adapted” for eachiteration. Further, in some embodiments, processing of the nonlinearmodel can be improved by creating frames of control samples oriterations, providing a different structure for the nonlinear model foreach frame, and adapting the estimated model parameters for eachiteration within a given frame. In this way, a linear approximation ofthe nonlinear model can be used for each frame, thereby easing theresource usage of adapting the nonlinear model at each iteration. Morespecifically, the estimated model parameters can be used in the controllaws, each control law applying the nonlinear model in a different way,to determine possible control signals, u_(se), and predict estimatedsystem outputs, y_(est_se). In particular, the nonlinear model caninclude a control portion, or calculation for a possible control signal,u_(se), and a prediction portion, or prediction of the system output,y_(est_se). The nonlinear model can take the estimated model parametertensor, Θ, as one of its inputs. The first output, the possible controlsignal, u_(se), can be passed from the control portion of the nonlinearmodel to the prediction portion of the nonlinear model to be used in theprediction of y_(est_se) (the second output of the nonlinear model). Thepossible control signal, u_(se), and the estimated system output,y_(est_se), are then passed to the selector module and used to identifythe different ones, numbers, and combinations of control laws (i.e., thepossible control signals generated therefrom) to apply to generate thecontrol signal, u_(out).

In this disclosure, a nonlinear model, and two derivations thereof,seven estimation laws, and eight control laws will be used as examples,but these are in no way limiting of the vast numbers of models,estimation laws, and control laws that can be implemented. Moreimportant, is how the models, estimation laws, and control laws worktogether to generate a control signal, u_(out), from inputs such asreference signal, system output measurements, and previous controlsignals, to name a few non-limiting examples.

As just one non-limiting example of how models, estimation laws, andcontrol laws interoperate, at startup, when a system's output is farfrom a desired reference signal, the adaptive engine 500 may u_(se) moreaggressive means of adapting the control signal such that speed ofconvergence is prioritized over stability (i.e., some combinations ofestimation laws and control laws may be given greater weight). As themeasured signal approaches the reference signal, the adaptive engine 500may decrease the priority given to rapid convergence, and instead turnmore to control that favors stability (i.e., different estimation lawsand control laws may be given greater weight). Eventually, those aspectsof the adaptive engine 500 that focus on rapid convergence may be almostentirely (or entirely) turned off, such that influence on the control,u_(out), is almost entirely (or entirely) stability oriented. This is anexample of just two priorities that can be balanced with time in theadaptive engine 500, and as one will see, there are numerous otherpriorities that can be selected or blended to generate the controlsignal based on the estimation laws and control laws that are givenpriority. As a more specific example, when a plasma processing recipe isrunning, it may start in an operation region that is relatively easy tomodel and track, and thus the adaptive engine 500 can primarily rely onestimation laws and control laws geared toward this operating region.However, after a period of time, the recipe may change the chamber gas,chamber pressure, power of the chuck, then the adaptive engine 500 mayshift toward different estimation laws and control laws geared towardthe new operating region. These adaptations are in addition to theadaptation seen in the estimated model parameter tensor, Θ, alone, whichwill start to see smaller changes from iteration-to-iteration as thenonlinear model approaches the actual behavior of the system. Thus, onesees that there are multiple ways that the adaptation engine 500 canadapt to nonlinear and dynamic system behavior.

In its most basic form, the adaptive engine 500 is a system thatreceives or accesses from memory, a reference signal, r (or stream ofreference signal signals), a measurement, y_(meas) (or stream ofmeasurements) of an output of the system being controlled (e.g., thenonlinear plasma load 104 in FIG. 4 ), a control signal, u_(out), from aprevious iteration, and produces a control signal (or “control”),u_(out), that is most likely to achieve a desired system responsecorrelating to the reference signal, r, rapidly and/or in a robustmanner (i.e., without instability). For instance, the adaptive engine500 could be used to control a plasma processing system 100, where thereference signal is a desired power being delivered to the plasma, suchas 1000 W, and the measurements are measures of power being delivered.The control, u_(out), may control power of a power supply, or in a MIMOsituation, may include the power and frequency of the power supply aswell as variable capacitor positions within a match network configuredto match impedance of the power supply to a nonlinear plasma load.Again, each of the reference signal, r, measurement, y_(meas), andcontrol signal, u_(out), can be a vector or tensor in embodiments withmore than one input and output, though for simplicity they will bediscussed in the singular throughout this disclosure.

The present disclosure, illustrated at a high level in FIGS. 5A-C,provides an adaptive engine 500 (or adaptation engine) including anadaptation law selector 502 and a selector module 508. The adaptationlaw selector 502 effectively selects a set of adaptation laws, eachcomprising a different combination of an estimation law and a controllaw.

Estimation Law Modules

The estimation laws are embodied in and implemented by estimation lawmodules 504 and the control laws are embodied in and implemented bycontrol law modules 506 (or sub-engines). The estimation law modules 504take an input regressor Ø and apply an estimation law to the inputregressor Ø to produce an estimated model parameter tensor, Θ, for anonlinear model of the actuators and/or system (e.g., a plasmaprocessing system). The estimated model parameter tensor, Θ, isdetermined for most estimation laws using at least a portion of theinput regressor, Ø, and an estimation error, ê, or cost function, J,either of which can be written in various forms, but typically comprisesome combination of two or more of the measured system output, y_(meas),an estimated system output for a given control law module, y_(est_se),and a reference signal, r. Typically, the measured system output,y_(meas), and the estimated system output, y_(est_se), are for aprevious iteration and thus in some cases can be written asy_(meas)(k−1) and y_(est_se)(k−1). Said another way, each estimation lawmodule estimates an estimated model parameter tensor, Θ, that minimizesan estimation error, ê, or cost function, J. This estimation is thenused by the nonlinear model in a corresponding control law module togenerate a possible control signal, u_(se), and to estimate an estimatedsystem output, y_(est_se), both of which are then used by the selectormodule to select a best one or combination of possible control signalsas the control, u_(out).

The estimated model parameter tensor, Θ, is described generally, butwill include values that are consistent between the estimation lawmodules 504 and the control law modules 506. In other words, the valuesof Ø at the control law modules 506 will match those values in Θ. Forinstance, a first control law may use r and y_(meas), so the incident Øis [r,y_(meas)] and the incoming Θ is [Θ_(r),Θ_(y_meas)]. Anothercontrol law may use r, y_(meas), and y_(d) (a filtered version ofy_(meas)), and thus Ø is [r, y_(meas), y_(d)] and the incoming Θ is[Θ_(r),Θ_(y_meas),Θ_(y_d)]. Further, because Θ is a tensor, it can takethe form of a 2-dimensional matrix such as the following:

$\Theta = \begin{bmatrix}\theta_{11} & \ldots & \theta_{1n} \\ \vdots & \ddots & \vdots \\\theta_{m1} & \ldots & \theta_{mn}\end{bmatrix}$

Or multi-dimensional matrices (not shown).

The controlled system can be the ones shown in FIGS. 1 and 4 or anyother system where the adaptive engine 500 provides a control signal,u_(out), (e.g., 454 in FIG. 4 or output of the control section 112 inFIG. 1 ) to one or more actuators. The input regressor Ø can include,for instance, a reference signal, r, a measurement of system output,y_(meas), an estimated system output for a control law module,y_(est_se), and a control signal u_(out) from a previous iteration(e.g., u_(out)(k−1)). However, other input regressors Ø can also beimplemented, for instance excluding the estimated system outputy_(est_se), and the input regressor Ø is typically a tensor. In moredetailed discussions of the control law modules 506 that will be seenlater, the input regressor Ø may be filtered at times, and the filteredversion of Ø can be referred to as w-though both are an input regressor.Filtering may be advantageous when a control law module (control law) issensitive to small perturbations, such that a filtered or smoothed inputregressor leads to more robust operation.

Control Law Modules

This disclosure now provides great detail surrounding the control lawmodules 506. Having calculated estimated model parameter tensors, Θ, byapplying estimation laws to the input regressor, Ø, the estimation lawmodules 504 for a given control law module 506, pass the estimated modelparameter tensors, Θ, to the corresponding control law module 506, whichthen applies the estimated model parameter tensors, Θ, to a control lawto generate a possible control signal, u_(se), or sub-engine controlsignal, for each estimation law (i.e., for each estimation law module504). There are typically one or more estimation law modules 504 (orestimation laws) for every control law module 506 (or control law). Forinstance, if seven estimation law modules 504 are implemented for eachof six control law modules 506, then at least forty-two possible controlsignals, u_(se), are generated and passed to the selector module 508.However, in some control law modules 506, more than one control law canbe implemented (e.g., see the TARC and Adaptive PID control law modulesdescribed later). Yet, even where multiple control laws are implementedin a single control law module 506, a possible control signal, u_(se),can be generated for each estimation law (i.e., for each estimation lawmodule 504).

The possible control signals, u_(se), from the one or more control lawmodules 506 are passed to a selector module 508 that provides a totalsystem control, or control, u _(out), as a best of the possible controlsignals, u_(se), or a best combination or blending of two or more of thepossible control signals, u_(se) (e.g., a weighted average,multiplication, or summation). This selection can be based on anestimated system error, ê_(out), or estimated system cost function,J_(out). The control, u_(out), is also the output of the adaptive engine500. As noted earlier, the control, u_(out), is typically a tensor forMIMO systems, although a single signal is possible, and in certainembodiments, can be implemented as the control signal(s) 454 seen inFIG. 4 .

The estimation error, ê, which is used by the estimation law modules 504to calculate the estimated model parameter tensor, Θ, can be calculatedfrom two or more of: (1) measured system output, y_(meas), (2) estimatedsystem output, y_(est_se), and (3) a reference signal, r. Morespecifically, the estimation error, ê, and hence Θ, can be based on adifference between two or more of these values. Each combination of anestimation law module 504 and a control law module 506 is associatedwith an estimated system output, y_(est_se), and the estimated systemoutput, y_(est_se), is calculated from the nonlinear model with thecorresponding possible control signal, u_(se), and estimated modelparameter tensor, Θ, as inputs. Thus, each combination of estimation lawmodule 504 and control law module 506 can produce distinct estimationerrors, ê, and hence a distinct estimated model parameter tensor, Θ. Insome determinations of the estimation error, ê, the estimated systemoutput, y_(est_se), calculated for each adaption law, can be passed tothe corresponding estimation law module 504 and used to calculate theestimation error, ê. As an example, the estimated system output,y_(est_se), could be an estimate of a measured power delivery to anonlinear plasma load such as 104 (e.g., estimate of signals measured bysensors 410). As noted earlier, the estimated system output, y_(est_se),is not limited to power parameters of a plasma processing system, and inother non-limiting examples, could include estimates of noise anddisturbance.

As seen, the adaptive engine 500 takes an input regressor, Ø, andproduces a control, u_(out), that is tailored to a given operatingregion (e.g., fast convergence v. stability; stable v. unstablezero-dynamics) based on selection of a best combination of estimationand control laws—this combination being referred to as an adaptationlaw. More specifically, the adaptive engine 500 provides a plurality ofcombinations of estimation law modules 504 and control law modules 506(i.e., a plurality of adaptation laws) that provide a plurality ofpossible control signals, u_(se), where each of these possible controlsignals, u_(se), are tailored for different control scenarios, and theselector module 508 then selects a one, or a combination, of thepossible control signals, u_(se), based on an estimated system error,ê_(out), as the control, u_(out).

Nonlinear Model

Further details of the nonlinear model are now provided. As describedabove, the estimation error, ê, is calculated from two or more of (1)measured system output, y_(meas), (2) estimated system output,y_(est_se), and (3) a reference signal, r, and where the estimatedsystem output, y_(est_se) is used, the estimation portion of thenonlinear model is used to estimate this value. Although the nonlinearmodel is not shown in FIG. 5A, it is a sub-component of each of thecontrol law modules 506. The location of the nonlinear model is notlimiting however, though the location may influence timing and resourceusage as well as the iteration of the estimated system output,y_(est_se), used. For instance, if the estimation portion of thenonlinear model estimates system output, y_(est_se), in the control lawmodules, as shown in FIG. 5A, then the possible control signals,u_(se)(k) (where k represents a value of the iteration), for a currentiteration are fed into the estimation portion of the nonlinear model toestimate y_(est_se). On the other hand, if the estimation portion of thenonlinear model estimated system outputs, y_(est_se), in the estimationlaw modules, as shown in FIG. 5B, then the possible control signals,u_(se(k−1)), for a previous iteration is fed back to the estimationportion of the nonlinear model to estimate y_(est_se). In either case,the estimated system outputs, y_(est_se), are used in the estimation lawmodules 504 to determine the estimation error, ê, and also passed to theselector module 508 to aid in determining which possible control signal,u_(se), to select, or which combination of possible control signals,u_(se), to combine and how to combine them (e.g., weighted average,multiplication, summation, etc.). Thus, the only differences betweenFIGS. 5A and 5B are the locations and directions of the estimated systemoutput, y_(est_se), arrows and the possible control signal, u_(se),arrows. For instance, the possible control signals, u_(se), are passedfrom the control law modules 506 to the estimation law modules 504 inFIG. 5B so that they can be used in in the estimation portion of thenonlinear models to calculate the estimated system outputs, y_(est_se).In FIG. 5A, the possible control signals, u_(se), are internallyprovided to the estimation portion of the nonlinear model in the controllaw modules 506. FIGS. 8A and 8B will provide further details to helpillustrate operation of the nonlinear models with 8A showing u_(se) ofthe current iteration's u_(se)(k) and the nonlinear model in the controllaw module, and 8B showing the previous iterations' u_(se)(k−1) and thenonlinear in the estimation law module. Although the estimation portionof the nonlinear model can execute in either the control law modules,the estimation law modules, or elsewhere, the control portion of thenonlinear model is part of the control law modules. For instance, insome embodiments, the operation of the estimation portion of thenonlinear model can occur somewhere within the adaptation law selector502, but outside either of the estimation law modules 504 and thecontrol law modules 506.

In FIGS. 5A and 5B there is one estimation law module 504 for eachcontrol law module 506. However, as shown in FIG. 5C, multipleestimation law modules 504 can provide outputs (e.g., Θ) to a givencontrol law module 506. Although only a first control law module 506 andits corresponding one or more estimation law modules 504 are explicitlyshown in FIG. 5C. Additional sets of one or more estimation law modules504 and corresponding control law modules 506 can also be implemented asshown via the “other estimation law modules” and “other control lawmodules” boxes. Each estimation law module 504 takes in input regressor,Ø, or a subset thereof, including values such as the reference signal,r, and the measured system output, y_(meas), and an estimated error, ê,and processes these through an estimation law to produce an estimatedmodel parameter tensor, Θ, for each estimation law module 504. Each ofthe estimated model parameter tensors, Θ, is passed to one of aplurality of control law modules 506, where two or more estimation lawmodules 504 can feed a single control law module 506. Each estimationlaw module 504 applies an estimation law, and each control law module506 applies a control law, such that every combination of an estimationlaw module 504 and a control law module 506 effectively implements an“adaptation law” and generates a distinct possible control signal,u_(se). Although multiple estimation law modules 504 can feed a singlecontrol law module 506 as seen in FIG. 5C, for simplicity, the remainderof this disclosure will extend the description of FIGS. 5A and 5B, whereone estimation law module 504 feeds one control law module 506. In lightof FIG. 5C and its description, those of skill in the art will also beable to implement the remainder of this disclosure as extensions of FIG.5C.

Referring to any of FIGS. 5A-C, a control law module 506 receives anestimated model parameter tensor, Θ, from each of one or more estimationlaw modules 504, along with the input regressor, Ø, or a subset thereof.It then applies these inputs to a control law to calculate a possiblecontrol signal, u_(se), for each of the estimated model parametertensors, Θ (i.e., for each of its corresponding estimation law modules504). The control law takes the form of a control portion of thenonlinear model where each control law uses a different variation of thesame basic control law portion of the nonlinear model. For instance, theControl Laws 1-4 described later in this disclosure are all variationsof the Model 1. However, these Control Laws can be modified/transformedto operate with other models, such as, but not limited to, Model 2. Thepossible control signals, u_(se), are then passed to the selector module508.

The input regressor, Ø, and subsets thereof are described generallyrelative to FIGS. 5A-5C since the estimation law module 504 or thecontrol law module 506, where the input regressor, Ø, or a subsetthereof, is provided, may dictate the values in the input regressor, Ø,or a subset thereof. For instance, the estimation law modules 504 oftenu_(se) two or more of the following, r, y_(est_se), and y_(meas_out), todetermine the estimation error, ê, which is then used, along with othervalues depending on the estimation law implemented in a given estimationlaw module 504, to determine estimation model parameter tensors, Θ. Inother words, Ø can be [r, y_(est_se), y_(meas)] when provided to theestimation law modules 504 in some embodiments, but [u_(out_k−1), r,y_(meas_out)] when provided to the control law modules 506. Thus,functionality is roughly the same whether Ø or a subset thereof isprovided to the estimation law modules 504 and the control law modules506. To better cover the various estimation law modules 504 and controllaw modules 506, this disclosure will continue to generalize the inputsto both modules as Ø, and those of skill in the art can easily optimizeresources and pipelining by providing more specific subsets thereof tothe two distinct sets of modules.

A more detailed understanding of the estimation portion of the nonlinearmodel will be had through understanding that the control samples can bebroken up into groups of frames, where each frame uses a differenttime-varying linear system, dependent on Θ, to approximate nonlinearbehavior over the frame. When these different linearized frames areconsidered as a whole, the net effect is an approximation of nonlinearbehavior, but where the adaptive engine 500 can process simpler,linearized versions of a nonlinear model. The time-varying linear systemcan be denoted by W_(m), and represents the solution to the system ofequations for {circumflex over (x)} and y_(est_se) shown earlier. Thestructure of the time-varying linear system, W_(m), or the structure ofthe A, B, and C matrices used in the system of equations for {circumflexover (x)} and y_(est_se), can be updated every frame—meaning that thestructure is constant within each frame. One illustrative structure ofW_(m) can be written as:

$W_{m} = \left\{ {\begin{matrix}{\overset{.}{x} = {{Ax} + {Bu}_{se}}} \\{y_{{est}\_{se}} = {Cx}}\end{matrix} = \left\{ \begin{matrix}{{\begin{bmatrix}1 & 0 & \theta_{1} \\1 & 0 & 0 \\0 & \theta_{2} & 1\end{bmatrix}x} + {\begin{bmatrix}1 \\1 \\1\end{bmatrix}u_{se}}} \\{\begin{bmatrix}1 & 0 & 0 \\0 & 1 & 0 \\0 & 0 & 1\end{bmatrix}x}\end{matrix} \right.} \right.$

See a similar form of this system written as Equations 12 and 13 in theTARC control law module discussion. One can see in this example that theC matrix is the identity matrix, that three controls are implemented(since the B matrix is of size 3), and that the A matrix includes twocomponents of the estimated model parameter tensor, Θ. Changing thestructure of W_(m) means that the locations of 1, 0, Θ, and fixedcoefficients (none are seen in the example above) in matrices A and Band optionally C (where the identity matrix is not used) are altered.For instance, if the above example structure was used in a first frame,changing the structure in a second frame could mean that the W_(m)structure is as follows:

$W_{m} = \left\{ \begin{matrix}{{\begin{bmatrix}1 & 0 & \theta_{1} \\0 & 1 & 1 \\0 & \theta_{2} & 0\end{bmatrix}x} + {\begin{bmatrix}1 \\1 \\1\end{bmatrix}u_{se}}} \\{\begin{bmatrix}1 & 0 & 0 \\0 & 1 & 0 \\0 & 0 & 1\end{bmatrix}x}\end{matrix} \right.$

As yet another example of changing the structure of W_(m), the adaptiveengine may determine that further adaptation of Θ₂ does not lead tosignificant improvement, and thus Θ₂ can be replaced with a fixedcoefficient (e.g., 0.88 in the below example)—meaning that it will nolonger be adapted.

$W_{m} = \left\{ \begin{matrix}{{\begin{bmatrix}1 & 0 & \theta_{1} \\0 & 1 & 1 \\0 & \text{.88} & 0\end{bmatrix}x} + {\begin{bmatrix}1 \\1 \\1\end{bmatrix}u_{se}}} \\{\begin{bmatrix}1 & 0 & 0 \\0 & 1 & 0 \\0 & 0 & 1\end{bmatrix}x}\end{matrix} \right.$

One will appreciate that since Θ₁ and Θ₂ are adapted or adjusted at eachcontrol sample or iteration, the overall effect of W_(m) sees smalladjustments in time. One also can see that when the structure changes, alarge change in W_(m) is seen. Since the nonlinear model depends on thetime-varying linear system, W_(m), structural changes to W_(m) at eachframe allow large changes in nonlinear behavior to be approximated bythe nonlinear model while sample-by-sample changes to the estimatedmodel parameter tensor, Θ, allow smaller nonlinearities to beapproximated by the nonlinear model.

The time-varying linear system, W_(m), can be calculated in a frameresynthesizer (see FIG. 6 ) or looked up in a table pre-populated by thecontroller designer. The time-varying linear system can then be passedto the nonlinear model at the control law modules 506 (FIGS. 5A and 5C)or the estimation law modules (FIG. 5B) at the start of each frame andthen held constant through a given frame. In some embodiments, differenttime-varying linear systems, W_(m), can be used for different controllaw modules 506, where the differences involve expansions of afundamental or most general form of the time-varying linear system,W_(m). For instance, see the differences between Model 1 and Model 2later in this disclosure. So, not only will the time-varying linearsystem, W_(m), change from frame to frame, but different combinations ofestimation law modules and control law modules can u_(se) differentforms of the time-varying linear system, W_(m), allowing differentcombinations of estimation and control law modules to achieve differinggoals in the linear approximations of the system's nonlinear behavior.This gives the adaptive engine 500 the ability to develop controlsignals, u_(out), for a wider variety of operating regions andconditions.

In the figures, providing the time-varying linear system as well aschanges to the structure thereof may both be symbolized by the sameW_(m).

Although this disclosure often uses Model 1, where the time-varyinglinear system, W_(m), is part of the estimation portion, Model 2 canalso be used, and will merely see the time-varying linear system, W_(m),used in the control portion instead. Details of both models arediscussed later in the disclosure.

Selector Module

The selector module 508 receives one or more possible control signals,u_(se), from the control law modules 506 and selects one or acombination of these possible control signals, u_(se), for output as thecontrol, u_(out). The selector module 508 can u_(se) the possiblecontrol signals, u_(se), the estimated system outputs, y_(est_se), andat least parts of the input regressor Ø including the reference signal,r, and the system output measurement, y_(meas), in an estimated systemerror, ê_(out) or estimated system cost function, J_(out), to select thepossible control signal, u_(se), or to select a combination of possiblecontrol signals, u_(se), (e.g., a weighted average thereof) thatminimizes the error or cost function. For instance, Equation 4 discussedlater will present a detailed example of an estimated system costfunction, J_(out), that can be used to select the best possible controlsignal, u_(se), or best combination of possible control signals, u_(se).Where processing resources are more limited, the selector module 508 mayselect a best possible control signal, u_(se), rather than a combinationof multiple possible control signals, u_(se). Where additionalprocessing resources are available, the selector module 508 may select abest combination of possible control signals, u_(se) which may includeselecting not only different combinations but different ways to combinethe possible control signals, u_(se).

Where a single possible control signal, u_(se), is selected, this signalis selected as the control, u_(out). However, where two or more possiblecontrol signals, u_(se), are selected, the control, u_(out), is formedby a blending of the possible control signals, u_(se). For instance,multiple possible control signals, u_(se), can be combined or blendedvia a “topology” such as, but not limited to, a weighted average, otheraverages, multiplication, summations, differences, divisions, integrals,derivatives, exponentials, complex functions, logarithms, series,statistical distributions, matrices, tensors, neural networks, nonlinearfunctions, graphs, maps, transformations, trees, to name a fewnon-limiting examples, or combinations thereof. For instance, Equation 5presents a detailed example of a means to combine possible controlsignals, u_(se), via a complex weighted average. However formed, thecontrol, u_(out), is then passed to the one or more actuators (e.g.,308) and fed back to the adaptation law selector 502 as an input to theestimation law modules 504 and the control law modules 506 to determinea next iteration of the u_(out). Because the control, u_(out), is usedas feedback for the next iteration, when input to the estimation lawmodules 504 and the control law modules 506, it may sometimes bereferred to as u_(out)(k−1).

Once the topology is selected, the selector module 508 can alsocalculate a total estimated system output, y_(est_out), in the same waythat the control, u_(out), was calculated (e.g., using Equation 7, whichis structurally similar to Equation 5). In other words, the totalestimated system output, y_(est_out), can be the estimated systemoutput, y_(est_se), corresponding to the selected one of the possiblecontrol signals, u_(se) (or selected adaptation law). Or where two ormore possible control signals, u_(se), are combined, the correspondingestimated system outputs, y_(est_se), can be combined in the samefashion to produce the total estimated system output, y_(est_out).

In some embodiments, one or more memory components (not shown), such aspipeline registers, can be arranged between the control law modules 506and the selector module 508, such that possible control signals, u_(se),and estimated system outputs, y_(est_se), can be temporarily stored,which either assists in parallelization in the selector module 508 orallows the selector module 508 to pull from previous outputs of thecontrol law modules 506 when the adaptive engine 500 sees repeated inputiterations (e.g., the same reference signal waveform repeats).

To carry out the above noted functionality, the selector module 508 mayimplement an optional control selector and combiner 516 (“CSC”) and anoptional topology selector and designer 518 (“TSD”). The TSD 518 canlook at previous controls (e.g., u_(out_k−1), u_(out_k−2), u_(out_k−3),etc.) and a total estimated system output, y_(est_out), for variouspossible topologies, and select a best topology, or the one most likelyto, when applied in the selector module 508, lead to a control, u_(out),that causes a measured system output, y_(meas), that is close to thetotal estimated system output, y_(est_out), or the reference signal, r.This may involve an error or cost function that compares the measuredsystem output, y_(meas), for a previous iteration, or the referencesignal, r, to the total estimated system outputs, y_(est_out),calculated for various possible topologies. More specifically, the TSD518 may analyze a cost function, such as Equation 4, to select anoptimal possible control signal, u_(se), or combination of possiblecontrol signals, u_(se) (in the form of a topology for combining thepossible control signals). The TSD 518 may provide this selection to theCSC 516, which then applies this topology to generate the control,u_(out), based on the topology and the possible control signals, u_(se).The topology may be embodied as a set of weights to be provided to theCSC 516, where the weights determine how possible control signals,u_(se), are combined or blended. In some embodiments, the topology caninclude averaging, multiplication, summations, differences, divisions,integrals, derivatives, exponentials, complex functions, logarithms,series, statistical distributions, matrices, tensors, neural networks,nonlinear functions, graphs, maps, transformations, trees, to name a fewnon-limiting examples, or combinations thereof. In other words, theselector module 508 predicts an output of the system that will resultfrom different control signals generated by different topologies, andthen selects the topology corresponding to a predicted output thatminimizes an error or cost function.

As part of the selection (or topology selection), the CSC 516 can u_(se)the estimated system outputs, y_(est_se), for each possible controlsignal, u_(se), (i.e., for each adaptation law) to determine anestimated system error, ê_(out), based on a measured system output,y_(meas_out), and u_(se) the estimated system error, ê_(out), toidentify the best of the possible control signals, u_(se), for selectionas the control, u_(out). Alternatively, or at the same time, a totalestimated system output, y_(est_out), can be found for each of variouscombinations of possible control signals, u_(se), and the combinationproviding a total estimated system output, y_(est_out), with thesmallest error from the measured system output, y_(meas), or thecombination providing a smallest error between the reference signal, r,and the measured system output, y_(meas), can be selected as thetopology that the CSC 516 uses to generate the control, u_(out).

Alternatively, the possible system outputs, y_(est_se) and/or the totalestimated system output y_(est_out), can be provided to the TSD 518,which can determine a possible control signal, u_(se), or combination ofpossible control signals, u_(se), that minimizes a cost functionrelative to the measured system output, y_(meas), or the referencesignal, r. If the TSD 518 selects the best possible control signal,u_(se), or combination thereof, the TSD 518 can send this selection backto the CSC 516 as a topology or set of weights. In turn, the CSC 516 canreturn weight-tuning values (w-tuning) to the TSD 518 that can be usedto adjust weights in a next iteration of topology selection. Weighttuning can increase the speed of the adaptive engine 500 and/or be usedto smooth transitions between control laws. Weight tuning can also beused to smooth transitions between u_(se).

It should be appreciated that the measured system output, y_(meas_out),can be n-dimensional and is not limited to a power output from a powersupply or match network, or power delivered to a plasma load. Othermeasured system outputs, y_(meas_out), can be composites of multiplemeasured values as well as internal actuator measurements such as powerdissipation in a DC section, to name one non-limiting example.

In some embodiments, adaptation or adaptation gain, or the influence ofthe adaptive engine 500, can be selected based on the measured systemoutput, y_(meas), approaching a target value(s) (e.g., reference signal,r, or total estimated system output, y_(est_out)). In other words, theadaptation or adaptation gain, or the influence of the adaptive engine500, can be selected based on an actual system error, e_(out). Inparticular, some, but not all estimation laws can include an adaptationgain, F, that influences the adaptation from a given estimation law.When the measured system output, y_(meas), is far from the targetvalue(s), the adaptation gain, F, can be large (or increased) and thusthe estimation laws in the estimation law modules 504 have a stronginfluence on the control signal, u_(out). As the measured system output,y_(meas), approaches the target value(s), the adaptation gain, F, can bedecreased, similar to how one pulls back on a boat's throttle whenapproaching a dock. Said another way, when the actual system error,e_(out), is greater than a threshold, the adaptation gain, F, can beincreased, and when the actual system error, e_(out), is less than thethreshold, then the adaptation gain, F, can remain unchanged. In oneembodiment, an optional adaptation influence control 510 can look at theactual system error, e_(out), or difference between a reference signal(e.g., r) or reference signal stream and a measured system output (e.g.,y_(meas)) and generate the adaptation gain, F, based on the actualsystem error, e_(out). Alternatively, the optional adaptation influencecontrol 510 can look at an error or difference between the referencesignal, r, and a total estimated system output, y_(est_out) (seeEquation 4 for instance). In yet other embodiments, the error ordifference can be based on the estimated system output, y_(est), and themeasured system output, y_(meas). In some embodiments, the adaptationinfluence control 510 can look at two or more of these errors (e.g.,Equation 4 is a cost function that considers two of these errors). Theadaptation gain, Γ, can be passed to the estimation law modules 504 andused in certain ones of the estimation laws to determine the estimatedparameter tensors, Θ. The adaptation gain, Γ, can be positive values ≤1.

Optional initialization 512 can store previous values such as a control,u_(out), total estimated system output, y_(est_out), and the adaptationgain, Γ, to name three non-limiting examples. These can be accessed asinitial conditions for a subsequent frame when the adaptation lawselector 502 returns to the same operating conditions. In an embodiment,the initialization 512 can store these initial conditions in a TSP-RAM.The initialization 512 can pass these values to the adaptation lawselector 502 and/or the selector module 508, and more specifically tothe control law modules 506.

There are at least two feedback loops illustrated in FIGS. 5A-C. First,the control, u_(out), can be fed back to the adaptation law selector502, for instance, as part of the input regressor, Ø, to aid ingenerating a next iteration of the estimated model parameter tensors, Θ.Second, the estimation portion of the nonlinear model can pass anestimated system output, y_(est_se), based on the possible controlsignals, u_(se), back to the corresponding estimation law modules 504.Like the control, u_(out), that is fed back, the estimated systemoutputs, y_(est_se), can be used in the estimation law modules 504 togenerate the next iteration of estimated model parameters, Θ. Theestimated system output, y_(est_se), can also be passed forward to theselector module 508. An additional optional feedback loop may providethe control, u_(out), to the optional adaption influence control 510,along with inputs such as r, y_(meas), and y_(est_out). These inputs canbe used to generate an adaptation gain, Γ, that influences the strengthof adaptation of certain of the estimation laws in the estimation lawmodules 504. Yet another optional feedback loop can provide the control,u_(out), to an initialization 512, which, as discussed earlier, usesthis to provide initial conditions to the control law modules 506 andthe selector module 508.

While most of this disclosure discusses the passing of estimationparameters, Θ, to the control law modules, in some embodiments, eachestimation law module can also pass derivatives, Θ′, of the estimationparameters, Θ. The derivatives, Θ′, can be used to increase an accuracyand speed of convergence to a target system behavior. Thus, where [Θ] isseen in the figures, this tensor can be replaced by [Θ,Θ′] in someimplementations.

Synthesized Frames

FIG. 6 illustrates an alternative adaptive engine that splits controlsamples, and certain aspects of the nonlinear model, into frames. Theadaptive engine 600 can include details as shown and described, forinstance, in any of FIGS. 5A-C. However, a frame resynthesizer 650 canbe arranged to precede the adaptive engine 600 and create synthesizedframes from the input regressor, such as, but not limited to including,the reference signal, r, and the measured system output, y_(meas).Synthesized frames can include blocks of input data that may or may notbe repeated in time. For instance, for a triangle wave reference signalwaveform, a synthesized frame might capture the rising and falling edgesof the triangle wave and might apply filters, such as smoothing filtersto make the synthesized frame easier to work with (e.g., smoother ormore linearized). More importantly, each frame can correspond to anumber of control samples or samples of the reference signal, r.Further, certain operations of the adaptive engine 600 can bepreprocessed or only processed once per frame. For instance, atime-varying linear system, W_(m), of the nonlinear model can bepre-determined or set by a controller designer and stored in a lookuptable, such that during operation, the adaptive engine 600 can access atime-varying linear system, W_(m), for every frame that is processed inthe adaptive engine 600. Alternatively, the frame resynthesizer 650 cancalculate the time-varying linear system, W_(m), of the nonlinear modelfor each frame and the adaptive engine 600 can then u_(se) theframe-specific time-varying linear system, W_(m), for the lifetime of aframe, and then switch to a new time-varying linear system, W_(m), whena new frame begins.

This time-varying linear system, W_(m), can also be thought of as thelinear approximation of the nonlinear model, and it stays constantthroughout a frame, while a nonlinear portion of the model, asrepresented by the estimated model parameter tensor, Θ, adaptsthroughout a frame. In other words, the model has a linear and nonlinearportion, and starts each frame with the linear portion known, butadapting the nonlinear portion toward convergence. Thus, adaptation islimited to the small unknown nonlinear portion, and does not need toalso adapt to the linear portion. Thus, adaptation is kept smaller thanin a non-bifurcated model, and as a result achieves convergence fasterand/or with u_(se) of loess processing resources.

Application of frames also assists in parallelization within theadaptive engine 600. A memory 652 can be used in combination with theframe resynthesizer 650 such that when a waveform returns to apreviously synthesized frame, the adaptive engine 600 can draw from thesynthesized frame in memory rather than requiring the frameresynthesizer 650 to resynthesize the inputs. This not only reducesprocessing resources, but can also decrease latency since less inputprocessing occurs when frames are accessed from the memory 652. FIG. 6helps to illustrate that any of the input regressors, Ø, in FIGS. 5A-C,or anywhere later in this disclosure, can also be implemented by thoseof skill in the art as synthesized frames.

Finding the time-varying linear system, W_(m), not only involvesdetermining a best linear model to approximate a region of the nonlinearmodel, but also finding a frame (or frame size) that leads to a bestlinear approximation. More specifically, the frame resynthesizer 650finds the largest frames that still allow accurate linear approximationsof the nonlinear behavior of the system. In other words, the frameresynthesizer 650 approximates the nonlinear system using a set oflinear models, but each frame and its linearization, may map todifferent numbers of control samples. More specifically, the frameresynthesizer 650 carries out an optimization procedure to find the bestcoefficients that describe the reference signal, r, and system outputmeasurements, y_(meas), for instance, by Equation 1A:

$\begin{matrix}{\begin{bmatrix}\overset{.}{r} \\\overset{.}{x}\end{bmatrix} = {{\begin{bmatrix}0 & 1 \\{- \omega_{n_{r}^{2}}} & {{- 2}\xi_{r}\omega_{n_{r}}}\end{bmatrix}\begin{bmatrix}r \\x\end{bmatrix}} + {\begin{bmatrix}0 & 0 & \ldots & 0 \\\omega_{n_{r}^{2}} & \omega_{n_{r}^{2}} & \ldots & \omega_{n_{r}^{2}}\end{bmatrix}\left\{ u \right\}}}} & \left( {{Equation}1A} \right)\end{matrix}$

For the largest number of samples n_(new) in a frame.

Where:

-   -   r is the reference signal;    -   x is the internal mathematically constructed state to represent        a second order linear system;    -   ω_(n) is a natural frequency in [rad/s] for the reference        signal's linear approximation and is different than the filter        input regressor ω used elsewhere in this disclosure;    -   ξ_(r) is the damping ratio [unitless] of the reference signal's        linear approximation;    -   ω₁ and ξ_(r) are determined through the reference signal's shape        and/or desired user-specified waveform; and

{u} This is the input tensor (control inputs) and is different from theu_(se) and u_(out) discussed elsewhere in the disclosure. In most cases,{u} is a filtered version of the reference signal, r.

The frame resynthesizer 650 can carry out an optimization procedure tofind the best coefficients that describe the reference signal, r, andsystem output measurements, y_(meas), for instance, by Equation 1B:

$\begin{matrix}{\begin{bmatrix}\overset{.}{y} \\\overset{.}{x}\end{bmatrix} = {{\begin{bmatrix}0 & 1 \\{- \omega_{n_{y}^{2}}} & {{- 2}\xi_{y}\omega_{n_{y}}}\end{bmatrix}\begin{bmatrix}y \\x\end{bmatrix}} + {\begin{bmatrix}0 & 0 & \ldots & 0 \\\omega_{n_{y}^{2}} & \omega_{n_{y}^{2}} & \ldots & \omega_{n_{y}^{2}}\end{bmatrix}\left\{ u \right\}}}} & \left( {{Equation}1B} \right)\end{matrix}$

Where:

-   -   y is the measured system output (y_(meas) elsewhere in this        disclosure);    -   x is the internal mathematically constructed state to represent        a second order linear system;    -   ω₁ is a natural frequency in [rad/s] for the measured system        output linear approximation and is different than the filter        input regressor ω used elsewhere in this disclosure;    -   ξ_(r) is the damping ratio [unitless] of the measured system        output linear approximation;    -   ω₁ and ξ_(r) are determined through the reference signal shape        and/or desired user-specified waveform; and    -   {u} is the input tensor (control inputs) and is different from        the u_(se) and u_(out) discussed elsewhere in the disclosure.

Outputs of the frame synthesizer 650 can also include tensors W_(m) (andits filtered variation Q_(m)), and the L, A, B, and C matrices. Thematrices A, B, and C can be used whenever the system is parametrized bythe state equations given by {dot over (x)} and x.

The new resynthesized frames will consist of the coefficients inEquation 1A or 1B whose duration is n_(new), in addition for thereference signal, r, system output measurements, y_(meas), and controls,u_(out), over that length of time. This ensures that each frame is alinear region of the process. Thus, all frames will u_(se) differenttime-varying linearized approximations of nonlinear system behavior thatclosely approximate the nonlinear system behavior. Adaptation in a framemeans that the time-varying linear system starts each frame from thislinear approximation and adapts toward an approximation of the truenonlinear process model via adaptation of the model parameter tensor, Θ.This makes the adaptation much faster and can guarantee convergence(since the adaptation does not have to estimate the linear part, onlythe nonlinear augmentation). The parameters resulting after adaptationconverges within a frame and Θ becomes virtually constant, can be storedin a memory, such as memory 652, to be used whenever the referencesignal, r, returns to these resynthesized frames during the referencesignal sequence. In other words, the estimated parameter tensor, Θ, onceconvergence is achieved, along with the corresponding structure of thetime-varying linear system, can be reused if a similar or identicalframe of the reference signal, r, is seen again. Said another way, onceadaptation of a frame is complete or converges, the knowledge gainedfrom that adaptation can be used again in subsequent similar frames,thus avoiding the need to perform adaptation again when similar framesare seen.

Although this disclosure often discusses a reference signal, r, it isalso feasible for a user to specify more abstract or general desires ofthe system output. In these cases, the adaptive engine can synthesizethe user's specifications into a desired reference waveform, y_(est_se),and this can replace or be used alongside the reference signals, r. Thedesired reference waveform, y_(ref), can be written as:

y _(est_se) =W _(m)(t)u _(se)+Δ  (Equation 2)

Where ∥Δ∥ is finite and represents the plasma generator/match/chambernonlinearity or uncertainty beyond any linear representation given byW_(m)(t)u_(se). The value u_(se) is the state's desired steady statevalue which in standard plasma generator terminology is referred to asthe power state and is a set of values provided by the user. In otherwords, the adaptive engine can provide at every collocation time orevery control sample, a linear model W_(m)(t) that makes/forms theclosest linear model of y_(est_se). Said another way, the adaptiveengine provides models that are time-varying stable and strictly properrational linear sample time invariant.

In some embodiments, one or more of a setpoint streaming module, aprecomputing engine (e.g., used to determine the A(t), B(t), C(t), K(t),L(t), F(t) matrices/tensors), and a frame synthesizer may be implementedon a Central Processing Unit (CPU). This allows the CPU, rather than anField Programmable Gate Array (FPGA), to handle the heavy/intensivecomputations in an offline (or pseudo-offline) manner. On the otherhand, the FPGA is better suited for performing simpler calculations in avery rapid manner (e.g., real-time or substantially real-time). Theprecomputing engine on the CPU sends the A(t), B(t), C(t), K(t), L(t),and/or F(t) matrices/tensors to the adaptive engine running on the FPGA.In some cases, the CPU also stores these matrices/tensors at a frameprocessor of the FPGA, for instance, in a TSP RAM of the frameprocessor. This allows the adaptive engine and/or the control lawmodule/sub-engine to access the precomputed matrices in real time orsubstantially real time. Said another way, the precomputing engine onthe CPU generates the structure of the A, B, and C matrices, and hencethe time-varying linear system, W_(m), for every frame.

FIG. 7 illustrates a method of adaptive control, and in some particularembodiments, of controlling one or more actuators controlling a system(e.g., a plasma processing system and/or power supply for the plasmaprocessing system) via an adaptive engine. The method 700 can start withselection of a new frame and a best linear approximation of the systembehavior over the new frame (Block 701). In other words, a structure ofW_(m) is selected. This structure can be calculated in a frameresynthesizer or accessed from an empirically derived lookup table. Themethod 700 can include estimating an estimated model parameter tensor,Θ, for every control sample of a nonlinear model (Block 702). Theestimating can be based on an estimation law that is a function of anestimated error, ê, or cost function, J, and can be implemented in anestimation law module. The estimated model parameter tensor, Θ,comprises estimated parameters of a nonlinear model such as, but notlimited to, r, y_(meas), y_(est_se), and u_(out). The method 700 canfurther generate a possible control signal, u_(se), using a controlportion of the nonlinear model (Block 704) and generate an estimatedsystem output, y_(est_se), using an estimation portion of the nonlinearmodel (Block 706). These two values can be calculated from a controlportion and an estimation portion of the nonlinear model, respectively.Both portions of the nonlinear model are functions of at least theestimated model parameter tensor, and the estimation portion can also bea function of the possible control signal, u_(se), from the controlportion. The control portion can also take the input regressor, Ø, asone of its inputs. The control portion of the nonlinear model can beimplemented in a control law and more specifically in a control lawmodule. The estimation portion of the nonlinear model can also beimplemented in the control law and the control law module, though it canalso be implemented in the estimation law module or outside of both thecontrol law module and the estimation law module. The method 700 canthen select (1) a best possible control signal, u_(se), from a setincluding the possible control signal, u_(se), and additional possiblecontrol signals, u_(se), or (2) a best combination of possible controlsignals, u_(se), blended from two or more of the set (Block 708). Theblending can be based on a topology that can include averaging,multiplication, summations, differences, divisions, integrals,derivatives, exponentials, complex functions, logarithms, series,statistical distributions, matrices, tensors, neural networks, nonlinearfunctions, graphs, maps, transformations, trees, to name a fewnon-limiting examples, or combinations thereof. The topology can beselected based on total estimated system output, y_(est_out), for eachof multiple possible topologies, and then comparing this estimate,y_(est_out), to the reference signal, r, the measured system output,y_(meas), or a combination of these (referred to as estimated systemerror, ê_(out)). For instance, a specific example using all three ofthese values is shown in Equation 4, where a cost function, J_(out) oftwo errors is used.

The adaptation of Θ described in Blocks 702-708 can be repeated for alliterations or control samples in a frame (repeat 702-708 until Decision710=Yes). This adaptation leaves the linear approximation (or structureof W_(m)) constant through a frame, but adapts Θ at each control samplein the frame until the bifurcated nonlinear model converges on thesystem's nonlinear behavior. At the end of the frame (Decision 710=Yes),a new linear approximation (structure of W_(m)) is calculated oraccessed, and adaptation of Θ again restarts from the baseline of thelinear approximation until convergence on the nonlinear system behavioris achieved. The final Θ can be stored along with a mapping to the frameand the structure of W_(m), such that these values can be recalledshould the reference signal underlying the frame be subsequently seen.

Estimation Law Modules

FIGS. 8A and 8B can be used to provide further detail of certainembodiments of the estimation law modules and the correspondingestimation laws. At a high level, an estimation law is a means ofestimating parameters for a nonlinear portion of a nonlinear model ofthe system (this model having a linear and a nonlinear portion). Controllaws take these estimated parameters and generate possible controlsignals therefrom, predicted to achieve a desired outcome from thesystem (e.g., minimize an error between a reference signal and ameasured output of the system). The estimated parameters along with thepossible control signals can also be used in an estimation portion ofthe nonlinear model to estimate one or more system outputs predicted toresult from the possible control signals.

Both modules 804, 806 can operate and be described similarly to thecorresponding components in FIGS. 5A-C. Although only one estimation lawmodule 804 and one control law module 806 are shown, multiple estimationlaw modules 804 and control law modules 806 would be found in a typicaladaptation law selector. One or more estimation law modules 804 can bepaired with each of the control law modules 806. Using differentcombinations of estimation law modules 804 and control law modules 806,the adaptive engine 500 effectively enables handling a wide variety ofcontroller needs and the ability to quickly switch between combinationsof estimation laws and control laws—the combinations being referred toas adaptation laws as shown via brackets in FIGS. 8A and 8B.

The estimation law module 804 can include an optional smoothing filterbank 810, one or more estimation law banks 812, and optionally one ormore estimation laws filtering banks 814. The optional filters 810, 814can provide filtering of the input and outputs from the one or moreestimation law banks 812. Namely, the optional smoothing filter bank 810can apply H{∘}, L⁻¹{∘} and WL{∘} to the input signals/regressors suchthat derivative terms are not noisy and do not have instantaneousspikes. H is a filtering operator and is designed by the user to achievethe fastest response possible for a given process time constant. Fordifferent control entities (e.g., rail, drive, frequency, match network,etc.), H{∘} will generate different filter parameters. It can beimplemented as a zero-phase lag filter. This guarantees smoothness andcontinuity of the inputs/regressors. This filter can be as simple as abiquad, or a first order time constant, though these two examples arenot limiting. However, in other filters, adaptive time constant filterscan be used based on a cost function. Each filter is designed to be bestsuited for the corresponding estimation portion 808 in FIG. 8A or FIG.8B.

The one or more estimation law banks 812 can take the input regressor,Ø, or an unfiltered version thereof (e.g., ψ), and apply it to anestimation law to estimate model parameter tensors, Θ, of the nonlinearmodel. Depending on the estimation law, the estimation law bank 812 mayalso receive the adaptive gain, Γ, and u_(se) this in the estimation ofthe estimated model parameter tensors, Θ. The input regressor, Ø, mayinclude components such as r, y_(est_se), and y_(meas), and from thesean estimation error, ê, can be determined. Depending on design, theestimation error, ê, can be determined from various differences betweentwo of these three values, for instance, the four estimation errors 1-4described below relative to the Estimation Law 1. In one embodiment,three estimation law modules 804 each having one of three nonlinearmodels can feed a single control law module 806. Seven estimation lawscan be distributed amongst these three estimation law modules 804 in oneexample, such that one or more estimation laws are applied to each ofthe nonlinear models, and the three estimation law modules 804 produceseven estimated model parameter tensors, Θ.

One or more estimation laws filtering banks(s) 814, one for each of theone or more estimation law banks 812, can be included at an output ofthe one or more estimation law banks 812. These optional filters 814 cansmooth the resulting estimated model parameter tensors, Θ, or createpersistent excitations such that the estimated model parameter tensors,Θ, converge to their actual values, and/or pass them through aprojection operator to make their values bounded and avoid drift. Thepurpose of this filtering 814 is to ensure that the possible controlsignal, u_(se), computed in the corresponding control law module 806, issufficiently rich of order N (i.e., contains N/2 distinct frequencies)which enforces the input regressor signal given by:

Ø_(u) =H _(Pe) {u}  (Equation 3)

Where Ø=[Ø_(u), Ø_(y), Ø_(r0)] is a tensor of the Ø_(u), Ø_(y), Ø_(r0)tensors, and Ø=H{φ} with H=[H_(u), H_(y), H_(r0)] and φ=[u, y, r₀].Where u is a tensor of all inputs (control) and their derivatives, y isa tensor of all measurements and their derivatives, and r₀ is a tensorof all extraneous entities (exogenous or internal) and theirderivatives.

In some embodiments, an estimated model parameter tensor, Θ, can beanother input to the nonlinear model.

An optional and non-illustrated feature is to select a law combinationin the optional one or more estimation law filtering banks 814 thatdiffers from iteration to iteration so as to minimize a cost function,such as a cost function that includes multiple summation operation atleast one of which is a function of ê(k).

The control law module 806 passes the possible control signal, u_(se),to the selector module (e.g., 508), which determines which possiblecontrol signal, u_(se), or which combination of possible controlsignals, u_(se), is used to generate the control, u_(out). Eachestimation law module 804 also passes its estimation model parametertensor, Θ, back to its input, either in real-time or via memory (notshown). This feedback allows the value to used in the next adaptationiteration. The memory can be a pipeline register, such as a TSP-RAMblock.

The nonlinear model can be split into a control portion 805 and anestimation portion 808. The control portion 805 can be found in thecontrol law 818 and the estimation portion 808 can be found in thecontrol law module 806 (in FIG. 8A) or in the estimation law module 804(in FIG. 8B). The estimation portion 808 can be used to generate anestimated system output, y_(est_se), for each combination of estimationlaw module 804 and control law module 806 (i.e., for each adaption law).The result can be passed forward to the selector module (not shown) andback as an input to a next iteration of the estimation law module 804,for instance, as part of the input regressor, Ø. This estimation canoccur almost anywhere, and thus FIGS. 8A and 8B provide but two examplesof where the estimation portion 808 can be used to estimate theestimated system output, y_(est_se) (in the control law module 806 inFIG. 8A and in the estimation law module 804 in FIG. 8B). However, thisestimation could also take place outside either of these modules. Onedistinction between FIGS. 8A and 8B, is that different iterations of thepossible control signal (u_(se_k) versus u_(se_k−1)) are used in theestimation, depending on where it takes place. In FIG. 8B, where theestimation using the estimation portion 808 occurs in the estimation lawmodule 804, the possible control signal, u_(se_k−1), for a previousiteration can be used, whereas in FIG. 8A, where the estimation usingthe estimation portion 808 occurs in the control law module 806, thepossible control signal, u_(se_k), for the current iteration can beused. The possible control signal, u_(se_k) or u_(se_k)_1, can begenerated by the control law 818 in the control law module 806 and canbe fed back to the estimation portion 808 in real time or via memory. Insome variations of the estimation portion, a linear portion of themodel, W_(m), may be used in the estimation, and this linear portion,W_(m), may be pre-calculated in a frame resynthesizer or access from anempirically derived lookup table. The same linear portion of the model,W_(m), is used for all iterations of a given frame, and then changed fora next frame.

Lower latency may be possible, and fewer memory resources used, if theestimation portion 808 is applied to generate the estimated systemoutput, y_(est_se), in the control law module 806 as shown in FIG. 8A.In this case, the estimation portion 808 can take the possible controlsignal, u_(se_k), for the current iteration and estimate a possiblesystem output, y_(est_se). In some instances, this may be faster thanthe variation shown in FIG. 8B.

While most of this disclosure discusses the passing of estimated modelparameter tensors, Θ, to the control law modules, in some embodiments,each estimation law module can also pass derivatives, {dot over (θ)}, ofthe estimated model parameter tensors, Θ. The derivatives, {dot over(θ)}, can be used to increase an accuracy and speed of convergence tothe system behavior. Thus, where [θ] is seen in the figures, this tensorcan be replaced by the more effective tensor [θ, {dot over (θ)}] in someimplementations.

Exemplary estimation laws 1-6 below show some non-limiting examples ofestimation laws that can each be implemented in the estimation lawmodule(s) 804 or 504. As seen, estimation laws are generally a functionof the estimation error, ê, and/or the input regressor, Ø, and producean estimated model parameter tensor, Θ, and optionally its derivative,{dot over (θ)}. Estimation laws can be implemented in the estimation lawbanks 812 and can be embodied in software, firmware, physical logiccircuits, or a combination of these. For instance, in a simplest case,an estimation law may involve matrix multiplication of the estimationerror, ê, and the input regressor, Ø (e.g., see Estimation Law 1).However, other estimation laws may involve more complicated interactionsbetween these values as well as intermediary steps and decisions enroute to generating the estimated model parameter tensor, Θ.

Although the estimation law banks 812 can implement any number ofestimation laws, below are a few non-limiting examples:

{dot over (θ)}=ΓêØ  (Estimation Law 1)

Where the estimation error, ê, can be written as any of the following:

$\begin{matrix}{\hat{e}\overset{\Delta}{=}{y_{meas} - y_{est\_ se}}} & \left( {{Estimation}{Error}1} \right)\end{matrix}$ $\begin{matrix}{\hat{e} = {r - y_{est\_ se}}} & \left( {{Estimation}{Error}2} \right)\end{matrix}$ $\begin{matrix}{\hat{e} = {y_{meas} - y_{est\_ se} - {W_{m}L{\hat{e}}_{km}n_{s}^{2}}}} & \left( {{Estimation}{Error}3} \right)\end{matrix}$ $\begin{matrix}{\hat{e} = \frac{y_{meas} - y_{est\_ se}}{m^{2}}} & \left( {{Estimation}{Error}4} \right)\end{matrix}$

In other words, the estimation error, ê, can involve a differencebetween two of the following three values or tensors: r, y_(meas),y_(est_se).

The certainty equivalence principle suggests that unknown parameters ina control design can be replaced by their estimates. A hat above avariable or parameter indicates an estimate of an unknown parameter.

Where m and n_(s) are normalization terms, and the input regressor Ø hasbeen discussed previously and can include values such as, but notlimited to, r, y_(meas), and u_(out).

Another exemplary estimation law can be written as:

$\begin{matrix}{\overset{.}{\theta} = {- {\Gamma\left( {{R\theta} + Q} \right)}}} & \left( {{Estimation}{Law}2} \right)\end{matrix}$$\overset{.}{R} = {{{{{- \beta}Q} + \frac{\varnothing\varnothing^{T}}{m^{2}}}❘{R(0)}} = R_{0}}$$\overset{.}{Q} = {{{{{- \beta}Q} + \frac{y_{meas}\varnothing}{m^{2}}}❘{R(0)}} = Q_{0}}$

And a third can be written as:

$\begin{matrix}{\overset{.}{\theta} = {P\hat{e}\varnothing}} & \left( {{Estimation}{Law}3} \right)\end{matrix}$$\overset{.}{P} = {{{{- P}\frac{\varnothing\varnothing^{T}P}{m^{2}}}❘{P(0)}} = P_{0}}$${{And}e} = {{\frac{y_{meas} - y_{est\_ se}}{m^{2}}{or}\hat{e}} = {y_{meas} - y_{est\_ se} - {W_{m}L{\hat{e}}_{{km} - 1}n_{s}^{2}}}}$

Where m and ns are normalization signals.

Another estimation law can be written as:

$\begin{matrix}{\overset{.}{\theta} = {P\hat{e}\varnothing}} & \left( {{Estimation}{Law}4} \right)\end{matrix}$$\overset{.}{P} = {{{{- P}\frac{\varnothing\varnothing^{T}P}{m^{2}}}❘{P({reset})}} = {P_{0} = {\infty I}}}$$\begin{matrix}{\overset{.}{\theta} = {P\hat{e}\varnothing}} & \left( {{Estimation}{Law}5} \right)\end{matrix}$ $\overset{.}{P} = \left\{ \begin{matrix}{{\beta P} - {P\frac{\varnothing\varnothing^{T}P}{m^{2}}{{{\left. {P(t)} \right|} \leq R_{0}}}}} \\0\end{matrix} \right.$ $\begin{matrix}{\overset{.}{\theta} = {\Gamma_{1}\hat{e}\varnothing{signum}\left( r_{est} \right)}} & \left( {{Estimation}{Law}6} \right)\end{matrix}$ $\overset{.}{r} = {\Gamma_{2}\hat{e}\varepsilon}$$\overset{.}{\varepsilon} = {{\theta\varnothing} + r_{0}}$${{With}\hat{e}} = {{y_{meas} - y_{est\_ se} - {W_{m}L\hat{e}n_{s}^{2}{or}\hat{e}}} = \frac{y_{meas} - y_{est\_ se}}{m^{2}}}$

Where Γ₁, Γ₂, and Γ₃ are different ones of the adaptation gain, Γ,provided by the adaptive engine where they are generated.

Yet a final non-limiting example of an estimation law can be written as:

{dot over (θ)}=N(x)Γ₁ êØ

N(x)=x ² cos(x)

x=w+r ²Γ₂

{dot over (W)} _(m) =ê ² m ² |W(0)=W ₀

{dot over (r)}=N(x)Γ₂ êε

{dot over (ε)}=θØ+r ₀  (Estimation Law 7)

One sees that most of the exemplary estimation laws are written in termsof the derivative of the model estimation parameter tensor, {dot over(θ)}, and yet the model estimation parameter tensor, θ, is the output ofthe estimation law modules. Any estimation law of this sort can berewritten to give θ by taking the integral of {dot over (θ)} and hencethe estimation law module output for a given estimation law. In otherembodiments, as described earlier, θ and {dot over (θ)} can both begenerated by the estimation law modules, and hence by the estimationlaws. More specifically, the integral of {dot over (θ)} is θ_(k−1)+{dotover (θ)}, or the sum of Θ of the previous iteration and the derivativeof Θ.

Further, each estimation law, whether one of the examples above, or anyother estimation law, may have two versions. In a first version, m²=1and n_(s)=0 such that no normalization occurs, which has the advantageof faster adaption but less applicability to unstable plants and/orunbounded control signals. In a second version, m²=1+n_(s) ²>0, whichleads to slower convergence for stable plants and/or bounded controlsignals, but will allow control of unstable plants and/or unboundedcontrol signals. The adaptive engine can switch between these twoversions of any estimation law in real time to enable faster control.

Estimation laws can be modified to include robustness measures that canbe pipelined/resource shared/streamed when implemented in a real-timehardware (e.g., ASIC/FPGA) in a generic way that benefits fromoversampling. For instance, all can be processed within a control cycle.

Nonlinear Models

As noted earlier, the nonlinear model takes the estimated modelparameter tensor, Θ, and an estimation error, ê, or cost function, J,and generates a possible control signal, u_(se), and an estimated systemoutput, y_(est_se), estimated to result from the possible controlsignal, u_(se). The combination of the nonlinear model, an estimationlaw, and a control law can be referred to as an adaptation law.

The nonlinear model can be used to provide a possible control signal andan estimated system output (e.g., reflected power, phase offset betweendelivered and reflected power, etc.). To this end, the nonlinear modelhas a control portion and an estimation portion, that in a most generalform can be written as:

u _(se)=θ·Ø  (Control Portion of the Nonlinear Model)

y _(est_se)=θ·Ø or W _(m) {u _(se),Θ}  (Estimation Portion of theNonlinear Model)

In some cases, both parts are processed in the control law module, andin other cases the estimation portion can be processed outside thecontrol law module (e.g., sees FIGS. 5A and 8A). However, in others, thecontrol portion can be processed in the control law modules and theestimation portion can be processed in the estimation law modules (e.g.,see FIGS. 5B and 8B) or elsewhere in the adaptation engine.

From this generalized from of the model, one sees that both the controlportion and the estimation portion are functions of the estimated modelparameter tensor, Θ, and the input regressor, Ø. The control portiongives a control that a given sub-engine believes is most likely toproduce a system behavior most in line with the reference signal, r. Theestimation portion is an estimate of the system output should thepossible control signal, u_(se), be provided to the one or moreactuators.

However, this generalized form is actually a circular definition becauseØ for the control portion takes y_(est_se) as an input, and Ø for theestimation portion takes u_(se) as an input. To avoid this circulardefinition, there are two solutions: (1) either the control or theestimation portion can be rewritten as a function of inputs from aprevious iteration (e.g., Θ_(k−1) and Ø_(k−1)) while the other is basedon current iteration inputs (e.g., Θ_(k) and Ø_(k)); or (2) one of thecontrol or estimation portions can be written in terms of the otherportion. More specifically, this second solution may lead to Model 1being rewritten in terms of the possible control signal, u_(se), as:

y _(est_se) =W _(m) ·θ·ψ=W _(m) {u _(se),Θ}  (Estimation Portion Model1)

Where this expansion is made possible via knowledge that u_(se)=θ·ψ, andW_(m) is a time-varying linear system and is a strictly positive real(SPR) that is a solution to the Lyapunov Equations and is a function ofthe possible control signal, u_(se), and the estimated model parametertensor, Θ. The time-varying linear system, W_(m), can also be thought ofas a transfer function or a linear operator. The time-varying linearsystem, W_(m), can have a different structure for different frames suchthat its global effect is to approximate the nonlinear system, but to doso using different time-varying linear approximations at each frame,where the time-varying linear system, W_(m), changes with Θ at eachcontrol sample or iteration within a frame. For instance, W_(m), couldbe

$\frac{s + {20}}{\left( {s + 1} \right)\left( {s + 2} \right)}$

for a first frame,

$\frac{1}{s + 5}$

for a second frame, and

$\frac{1}{s^{2} + {2s} + 1}$

for a third frame. While the time-varying linear system, W_(m), has aconstant structure for a given frame, it is a function of Θ, whichadjusts or is adapted at every iteration or control sample. RecallingFIG. 43 , the time-varying linear system, W_(m), is adapted as afunction of Θ during each frame until convergence (where an unknownnonlinear portion of W_(m) is small enough to be ignored). The structureof this time-varying linear system, W_(m), changes from frame to frame.The net effect is a bifurcated nonlinear model that uses a differentlinear approximation in each different frame to account for largechanges in system nonlinear behavior and a nonlinear approximationachieved through adaptation of the estimated model parameter tensor, Θ,at each control sample or iteration of a frame to account for smallchanges in system nonlinear behavior.

For clarity, the control portion of Model 1 is the same as itsgeneralized form noted earlier:

u _(se)=Θ·Ø  (Control Portion of the Model 1)

As noted above, avoiding a circular definition of the generalized modelcan also be achieve by writing the control portion in terms of theestimation portion:

u _(se) =W _(m) ⁻¹ {y _(est_out)}  (Control Portion of the Model 2)

y _(est_se)=Θ·Ø  (Estimation Portion of the Model 2)

The control portion of Model 2 can also be written in terms of y_(meas)instead of the total estimated system output, y_(est_out). The controlportion of Model 2 may use W_(m) ⁻¹ as shown or an approximationthereof.

Regardless of whether Model 1 or 2 is used, the time-varying linearsystem, W_(m), is an input to either the estimation portion (Model 1) orthe control portion (Model 2).

Expanding on the estimation portion of Model 1, it will be appreciatedthat u_(se) is an input to the system W_(m), and this operation givesthe estimated system output, y_(est_se), based on the dynamic equation:

{dot over (x)}=Ax+Bu _(se)

y _(est_se) =Cx

where C can be the identity matrix for improved performance.

This means that

{dot over (y)}=Ay _(est_se) +Bu _(se)

So, W_(m){u_(se),Θ} leads to y_(est_se) by integrating {dot over (y)}.

Control Laws (Control Law Modules)

Each control law is implemented as a control law module, andspecifically as the control law 818 within that control law module. Eachcontrol law module applies the control portion of the nonlinear model,as modified into a distinct control law, to an estimated model parametertensor, Θ, and at least part of the input regressor, Ø, to generate apossible control signal, u_(se). In some cases, a control law module maybe configured to apply more than one control law (e.g., the TARC controllaw module discussed later can apply adaptive inversion laws, Eigenlaws, and Penalty laws) and produce a corresponding number of possiblecontrol signals, u_(se). Alternatively, an optional select control law816 may be used to select a preferred control law for the control lawmodule to apply such that the number of possible control signals,u_(se), is the same as seen in other control law modules. The optionalselect control law 816 is shown as preceding the control law 818, butcould also be arranged after the control law 818 and thereby filtermultiple u_(se) into a single u_(se).

Control laws take the estimated model parameter tensors, Θ, estimated bythe estimation laws in the estimation law modules, which are variationson the control portion of the nonlinear model, and generate possiblecontrol signals, u_(se), predicted to achieve a desired behavior fromthe system (e.g., minimize an error between a reference signal and ameasured output of the system).

The control law modules, examples of which will be detailed in FIGS.10-42 (also called sub-engines), implement control laws to generate thepossible control signals, u_(se), that are then passed from all controllaw modules to the selector module. Each control law module takes one ormore estimated model parameter tensors, Θ, from one or more estimationlaw modules, and passes each of the one or more estimated modelparameter tensors, Θ, through a control law (control portion of thenonlinear model) to give a possible control signal, u_(se). In otherwords, each estimation law leads to a at least one possible controlsignal, u_(se). These control laws can be implemented in software,firmware, physical logic, or a combination of these. The examples thatwill be described below and illustrated in FIGS. 10-42 providefunctional descriptions of the control laws as implemented in controllaw modules, and any of this functionality may be coded in software orfirmware, fabricated in physical logic, or some combination of these.Further, while the control law modules or sub-engines are described aspart of a larger adaptive engine, in some embodiments, the control lawmodules or sub-engines can operate independently, such that each on itsown can control one or more actuators of a power system.

To better appreciate control laws, their influence on the adaptiveengine, and the breadth of their variations, six exemplary, butnon-limiting, control laws can be written as follows starting withControl Law 1A for a TLMC (or Lyapunov) control module:

u _(se)=θω  (Control Law 1A)

Each of these control laws is based on a control portion of thenonlinear model that complements a corresponding estimation portion ofthe nonlinear model and typically the output of the control portion isan input to the estimation portion (or vice versa).

In Control Law 1A, ω overlaps with but is not identical to Ø. Inparticular, ω is a concatenation that can include some form ofu_(out_k−1), y_(meas), and r (i.e., often components of Ø). Forinstance, one or more of these values can be filtered before beingconcatenated into w. For instance, w may equal [u_(d), y_(d), y_(meas),r] where u_(d) and y_(d) are filtered or smoothed versions of u_(out)and y_(meas), respectively. Where Control Law 1A also makes u_(se) ofthe derivative of Θ, it can be written in the alternative as:

$\begin{matrix}{u_{se} = {{0\omega} + {\overset{.}{0}\chi}}} & \left( {{Control}{Law}1B} \right)\end{matrix}$ ${{Where}\chi} = \left\{ \begin{matrix}{{H\left\{ \omega \right\}} = \mathcal{L}^{- 1}} & \left. \left\{ \omega \right\} \middle| {{\dim_{- 1}(\theta)} > 1} \right. \\0 & {\left| {\dim_{- 1}(\theta)} \right. = 1}\end{matrix} \right.$

Control Laws 1A and 1B are detailed further in FIGS. 10A and 10B. Asecond exemplary control law for a TARC control law module, can actuallybe selected from three control laws 2A, 2B, and 2C and they can bewritten as:

u _(se) =[H{u _(out) }−

Q _(m) ]H ⁻¹ {u _(out) }−{circumflex over (P)}H ⁻¹ {e}  (Control Law 2A)

u _(se) =H{Q _(m)Ω}  (Control Law 2B)

u _(se) =H{−Q _(m) pinν(R){circumflex over (B)}Pê _(out)}  (Control Law2C)

In one embodiment, a best of Control Law 2B and 2C can be selected as:

$\begin{matrix}\begin{bmatrix}{H\left\{ {Q_{m}\Omega} \right\}} \\{H\left\{ {{- Q_{m}}{{pinv}(R)}\hat{B}P{\hat{e}}_{out}} \right\}}\end{bmatrix} & \left( {{Control}{Law}2B/2C} \right)\end{matrix}$

And a total control law based on 2A and the combination of 2B and 2C canbe written as a selection or combination of:

$\begin{matrix}\begin{bmatrix}{{\left\lbrack {{H\left\{ u_{out} \right\}} - {\hat{\mathcal{L}}Q_{m}}} \right\rbrack H^{- 1}\left\{ u_{out} \right\}} - {\hat{P}H^{- 1}\left\{ e \right\}}} \\{H\left\{ {Q_{m}\Omega} \right\}} \\{H\left\{ {{- Q_{m}}{pinv}(R)\hat{B}P{\hat{e}}_{out}} \right\}}\end{bmatrix} & \left( {{Control}{Law}2A/B/C} \right)\end{matrix}$

An augmentation of the above can be written as

$\begin{matrix}\begin{bmatrix}{{\left\lbrack {{H\left\{ u_{out} \right\}} - {\hat{\mathcal{L}}Q_{m}}} \right\rbrack H^{- 1}\left\{ u_{out} \right\}} - {\hat{P}H^{- 1}\left\{ e \right\}}} \\{H\left\{ {Q_{m}\Omega} \right\}} \\{H\left\{ {{- Q_{m}}{pinv}(R)\hat{B}P{\hat{e}}_{out}} \right\}}\end{bmatrix} & \left( {{Control}{Law}2A/B/C{Augmented}} \right)\end{matrix}$

Control Laws 2A, 2B, and 2C are detailed further in FIGS. 11A-13 .

A third exemplary control law for an L1 control law module can bewritten as:

u _(se)=θ_(u) _(out) u _(out)+θ_(y) _(d) y _(d) +θy _(pred) y_(pred)+Θ_(r) r  (Control Law 3)

And details of this Control Law 3 can be seen in FIGS. 14-15 .

A fourth exemplary control law for an Adaptive PID control law modulecan be written as:

u _(se) =u _(PID) _(k) −u _(FF) _(k) =[θ,θ₇][ω,ω₇]  (Control Law 4)

Where ω₇=H{u_(n) _(k−1) }

Details of the Control Law 4 can be seen in FIGS. 16-21 .

The input regressor, Ø, and subsets thereof are described generallyrelative to FIGS. 8A and 8B since the estimation law module 804 or thecontrol law module 806, where the input regressor, Ø, or a subsetthereof, is provided, may dictate the values in the input regressor, Ø,or a subset thereof. For instance, the estimation law modules 804 oftenu_(se) two or more of the following, r, y_(est_se), and y_(meas), todetermine the estimation error, ê, which is then used, along with othervalues depending on the estimation law implemented in a given estimationlaw module 804, to determine estimation model parameter tensors, Θ. Inother words, Ø can be [r, y_(est_se), y_(meas)] when provided to theestimation law modules 804 in some embodiments, but [u_(out_k−1), r,y_(meas)] when provided to the control law modules 806. Thus,functionality is roughly the same whether Ø or a subset thereof isprovided to the estimation law modules 804 and the control law modules806. To better cover the various estimation law modules 804 and controllaw modules 806, this disclosure will continue to generalize the inputsto both modules as Ø, and those of skill in the art can easily optimizeresources and pipelining by providing more specific subsets thereof tothe two distinct sets of modules.

Selection of Topology to Generate the Control

Returning to FIG. 5A, additional details of the selector module 508 arepresented. After the control law modules 506 select possible controlsignals, u_(se), the selector module 508 receives the one or morepossible control signals, u_(se), and performs further estimations toselect a best one of the possible control signals, u_(se), or a bestcombination of the possible control signals, u_(se), as the control,u_(out). In particular, the selector module 508 estimates a systemoutput based on different ones of the possible control signals, u_(se),or different combinations of multiple possible control signals, u_(se),and resulting error values for each of these estimations relative to adesired system outcome (e.g., minimizing an error between referencesignal and measured system output and/or minimizing an error betweenreference signal and estimated system output). This error is the systemoutput error, ê_(out), previously referred to. As an example of thisestimation and error determination, the selector module 508 can u_(se)the possible control signals, u_(se), the estimated system outputs,y_(est_se), the reference signal, r, and the system output measurement,y_(meas), in an error or cost function to select the possible controlsignal, u_(se), or to select a combination of possible control signals(e.g., a weighted average thereof) that minimizes the cost error or costfunction. For instance, Equation 4 discussed later will present adetailed example of a cost function that can be used to select the bestpossible control signal, u_(se), or best combination of possible controlsignals, u_(se). Where processing resources are more limited, it may bepreferable for the selector module 508 to select a best possible controlsignal, u_(se). Where additional processing resources are available, theselector module 508 may select a best combination of possible controlsignals, u_(se) (which may include selecting not only differentcombinations but different ways to combine the possible control signals,u_(se)). The combination or blending of multiple possible controlsignals, u_(se), can be governed by a topology such as, but not limitedto, a weighted average. In an embodiment, Equation 5 presents a detailedexample of a means to combine possible control signals, u_(se), via acomplex weighted average. Other forms of combination or blending caninclude, but are not limited to, other types of averages,multiplication, summations, differences, divisions, integrals,derivatives, exponentials, complex functions, logarithms, series,statistical distributions, matrices, tensors, neural networks, nonlinearfunctions, graphs, maps, transformations, trees, or combinationsthereof.

Whatever topology, or method of combining/blending is used to determinethe control, u_(out), is also used to estimate a total estimated systemoutput, y_(est_out). Specifically, the selector module 508 determines anumber and combination (or blending) of control law module 506 outputs(e.g., u_(se) and/or y_(est_se)) that minimizes the estimated systemerror, ê_(out), or estimated system cost function, J_(out). Forinstance, in a first iteration, a blending of three out of seven controllaw module 506 outputs may produce an total estimated system outputy_(est_out) (or estimated output) that is closest to the referencesignal r (that minimizes the estimated system error, ê_(out)), while ina second iteration, a blending of five out of seven control law module506 outputs may produce a total estimated system output y_(est_out) thatis closest to the reference signal r. Each of these represents adifferent topology and thus one sees that the selector module 508 mayselect a different topology for generating the control signal, u_(out),and estimated system output, y_(est_se), at each iteration (e.g., usingEquation 7, which largely mimics Equation 5).

The selected or blended control, u_(out), is then passed to the one ormore actuators (e.g., 308) and fed back to the adaptation law selector502 as an input to the estimation law modules 506 for u_(se) indetermining a next iteration of the control, u_(out).

In some embodiments, one or more memory components (not shown), such aspipeline registers, can be arranged between the control law modules 506and the selector module 508, such that possible control signals, u_(se),and estimated system outputs, y_(est_se), can be temporarily stored,which either assists in parallelization in the selector module 508 orallows the selector module 508 to pull from previous outputs of thecontrol law modules 506 when the adaptive engine 500 sees repeated inputiterations (e.g., the same frame or reference signal repeats).

In some implementations, the selector module 508 can distribute theabove-noted functionality between an optional control selector andcombiner 516 (“CSC”) and an optional topology selector and designer 518(“TSD”). The TSD 518 can look at previous controls, u_(out), and a totalestimated system output, y_(est_out), for various topologies, and selecta best topology, or the one most likely to, when applied in the selectormodule 508, lead to a control, u_(out), that causes a measured systemoutput, y_(meas), that is close to the total estimated system output,y_(est_out), or the reference signal, r. For instance, the TSD 518 mayanalyze an estimated system cost function, J_(out), such as Equation 4,to select an optimal possible control signal, u_(se), or combination ofpossible control signals, u_(se) (in the form of a topology forcombining the possible control signals). The TSD 518 may provide thisselection to the CSC 516, which dictates how selected possible controlsignals, u_(se), are to be combined or blended in the CSC 516 (alsoreferred to as applying the topology). For instance, the TSD 518 mayprovide a topology to the CSC 516, which looks at different topologiesfor combining or blending the possible control signals, u_(se), in theCSC 516 (e.g., a weighted average), and determines a best topology. Thistopology may be embodied as a set of weights to be provided to the CSC516, where the weights determine how possible control signals, u_(se),are combined or blended. In some embodiments, the topology can includeaveraging, multiplication, summations, differences, divisions,integrals, derivatives, exponentials, complex functions, logarithms,series, statistical distributions, matrices, tensors, neural networks,nonlinear functions, graphs, maps, transformations, trees, to name a fewnon-limiting examples, or combinations thereof. Equation 5 presents onenon-limiting example of applying a topology with weights, w_(nj) andw_(nn).

The CSC 516 in turn can estimate a total estimated system output,y_(est_out), based on the topology or weights and the total estimatedsystem outputs, y_(est_se), and provide this estimate, y_(est_out), tothe TSD 518 for u_(se) in determining a next iteration of the topology(e.g., in the cost function of Equation 4). Where the TSD 518 passesweights to the CSC 516, the CSC 516 can return weight-tuning values,w-tuning, to the TSD 518 that can be used to adjust weights in a nextiteration.

Alternatively, these estimates, y_(est_se) and/or y_(est_out), can beprovided to the TSD 518, which can determine a possible control signal,u_(se), or combination of possible control signals, that minimizes acost function relative to the measured system output, y_(meas), and/orthe reference signal, r. If the TSD 518 selects the best possiblecontrol signal, u_(se), or combination thereof, the TSD 518 can sendthis selection back to the CSC 516 as a topology or set of weights. Inturn, the CSC 516 can return weight-tuning values to the TSD 518 thatcan be used to adjust weights in a next iteration of topology selection.

In some embodiments, the selector module 508 can optimize the estimatedsystem cost function, J_(out), associated with topologies of the controllaws implemented by the control law modules 506. It does this byconsidering the possible control signals, u_(se), and finding acombination and means of combining them that optimizes the estimatedsystem cost function, J_(out). For instance, the estimated system costfunction, J_(out), may look at a difference or error between thereference signal, r, and a measured output, y_(meas), or between thereference signal, r, and a total estimated system output, y_(est_out).In another instance, the estimated system cost function, J_(out), canlook at both of these errors, for instance, as presented in Equation 4:

$\begin{matrix}{J_{{out}k_{p}} = \begin{bmatrix}{❘{r_{k} - y_{{est\_ out}_{k_{p}}}}❘} \\{❘{r_{k} - y_{{meas}_{k}}}❘}\end{bmatrix}} & \left( {{Equation}4} \right)\end{matrix}$

Where k is a value representing the iteration being analyzed,y_(est_out_k_p), is an estimated total output of the controlled systembased on a one of p topologies being analyzed, and the estimated systemcost function, J_(outk_p), can be analyzed for each of the p topologies.The one of the p topologies resulting in the minimum estimated systemcost function, J_(outk_p), is selected for generating the controlu_(out).

Each of the p topologies can involve a different weighted input of theestimated output, y_(est_se) from each of the control law modules. Insome cases, this can be a weighted average of the control law moduleoutputs, or a more complex mixing, such as multiplication of someoutputs and summing of other outputs. The weights can be denoted, w(distinct from w), and are the ones used in a previous iteration, k−1.

While it is possible to try every permutation of topologies, this wouldbe highly resource-consuming, and thus a preferred method uses anoptimization of the weights applied to the different control law moduleoutputs to analyze the cost function of Equation 4.

Given the weights, the selector module 508 can generate a controlsignal, u_(out), which in one embodiment, is given by the weighted sumshown in Equation 5:

u _(out)=(Σ_(n=1) ^(N)Σ_(j=1) ^(N) w _(nj) u _(j))+(Σ_(n=1) ^(N) w _(nn)u _(se) _(n) )  (Equation 5)

Where n is an index for the current possible control signal, u_(se), andj is an index for all other possible control signal, u_(se), and where Nis a total number of control laws. For instance, N=3 or N=7 in twonon-limiting embodiments. Recall that a control law is implemented byeach control law module, so another way to describe n and j is that nrepresents the possible control signal, u_(se), for a current controllaw module, and j represents the possible control signals, u_(se), forall other control law modules. The weights, w_(nj), and ω_(n) can beselected to minimize at each control sample, an estimated system error,e_(out), for instance as calculated via Equation 6:

|y _(meas) −y _(est_out) |=|y _(meas)−(Σ_(n=1) ^(N)Σ_(j=1) ^(N) w _(nj)y _(est_out) _(n) )+(Σ_(n=1) ^(N) w _(nn) y _(est_out) _(n) )|  (Equation 6)

Those of skill in the art will appreciate that the estimated systemerror, ê_(out) can be calculated in other ways. For instance, y_(meas)can be replaced by r in some embodiments. From Equation 6 it can be seenthat the total estimated system output, y_(est_out), can be given byEquation 7:

y _(est_out)=(Σ_(n=1) ^(N)Σ_(j=1) ^(N) w _(nj) y _(est_out) _(j))+(Σ_(n=1) ^(N) w _(nn) y _(est_out) _(n) )  (Equation 7)

Equation 7 can be seen to nearly mimic Equation 5—in other words thetopology applied to the possible control signals, u_(se), is alsoapplied to the estimates of total system output, y_(est_se). For bothEquations 5 and 7, the weights, w_(nj), and w_(n) can be set to 1 for aninitial iteration of the selector module 508, and in subsequentiterations, Equation 6 can be used to narrow in on more effectiveweights until the cost function in Equation 4 is minimized. Equation 5can then be used to provide a control signal, u_(out), from the selectormodule 508 based on the topology dictated by the optimized weights,w_(nj), and w_(nn).

Although not shown, the adaptive engine 500 can further include a CCSengine coupled to the selector module 508 that generates an exogenoussignal, that tries to enforce coherency, consensus, and synchronizationamong the different potential control signals, u_(se), based on theselected topology. In other words, the CCS engine provides an exogenoussignal to the selector module 508 to smooth discontinuities that mightarise as it switches between possible control signals, u_(se). The CCSengine can u_(se) the system output measurement, y_(meas), and aspectsof the input regressor, Ø, such as the reference signal, r, to determinethe exogenous. It should be appreciated that the exogenous is calculatedfor and applied to each of the possible control signals, u_(se). Forinstance, the exogenous can be a modifier of the weights applied to eachpossible control signal, u_(se), when multiple possible control signals,u_(se), are being combined or blended. For instance, in Equation 5, theweights, w, can be modified by the exogenous for each possible controlsignal, u_(se). In some embodiments, the functionality of the CCS engineand the exogenous can be implemented in the w-tuning.

With a more detailed appreciation of the nonlinear model, the estimationlaws, the estimation law modules, control laws and the control lawmodules, and the selector and combiner, an illustrative representationin FIG. 46 may further help explain these various aspects of thedisclosure. FIG. 46 shows an illustrative example of operation of anadaptive engine according to embodiments of this disclosure. Theadaptive engine 4600 enables multiple combinations of estimation andcontrol laws to be combined and then a best combination or combinationsare selected for u_(se) in determining a control signal, u_(se), for oneor more actuators, such as the actuators described in FIG. 4 . Inputs tothe adaptive engine 4600 can include a reference signal, r, (e.g., astream of setpoints), measurements of the system being controlled by theone or more actuators, y_(meas), and an estimated system output asdetermined by the adaptive engine 4600 in a previous iteration. Theseand other inputs can be concatenated or stored in tensor form, as inputregressor, Ø. Thus, one sees that the adaptive engine 4600 at the mostbasic level, takes an input regressor, Ø, and produces a control signal,u_(out). But the adaptive engine 4600 also achieves this using uniquebifurcation of duties such that parallelization is optimized, andcertain calculations are pre-processed, or processed at lower speeds,while others are calculated in real-time. For instance, the nonlinearmodel of the actuator(s) and/or system controlled by the actuator(s) canbe difficult to describe in one or even a small series of equations.Instead, the nonlinear model is broken into frames of sample points andfor each frame, the nonlinear model is approximated by a time-varyinglinear system, W_(m), that is based on the estimated model parametertensor, Θ, and is adapted through the frame until the time-varyinglinear system, W_(m), represents an accurate approximation of thenonlinear behavior for that frame (i.e., when Θ becomes constant formultiple control samples or iterations). In this way, the modelapproximates the nonlinear nature of the actuator(s) and/or system,while easing the processing burden of control by using a linearapproximation that is adapted toward the nonlinear system behavior withevery iteration of Θ. More specifically, for each frame of samplepoints, a frame resynthesizer 4602, selects a structure of atime-varying linear system, W_(m), (i.e., which elements in a givenframe's W_(m) matrix or matrices are ones and zeros). Alternatively, thestructure of the time-varying linear system for each frame can beselected by a designer based on empirical study of the actuator(s) andsystem. Either way, for the sample points of a given frame, atime-varying linear model is used that approximates the nonlinearbehavior while converging on that nonlinear behavior via adaptation ofΘ. In other words, any unpredicted or averaged out nonlinear behavior isapproximated through the “theta” parameter adaptation at every controlsample.

The engine 4600 can include various estimation law modules 4606, thoughonly one is shown in this abbreviated illustration. The estimation lawmodule 4606 applies an estimation law, such as {dot over (θ)}=ΓêØ, toestimate a best value for the parameters (estimated model parametertensor, Θ) of the nonlinear model, or more specifically, the linearizedversion of the nonlinear model for the given frame. Each estimation law,not just the one shown, is a function of an error, ê, or a costfunction, J. Whichever one is used, the error or cost function is afunction of two or three of the following: (1) reference signal, r; (2)measured system output, y_(meas), from a previous iteration or previouscontrol sample; and (3) estimated system output, y_(est_se), for aprevious iteration or previous control sample. Where the estimatedsystem output, y_(est_se), is used in the error or cost function, thisprediction can come from a prediction portion of the model 4608B. Inother words, the estimation law module 4606 adapts the estimated modelparameter tensor, Θ, every iteration. Since the frame resynthesizer, orthe designer, selects a new time-varying linear system of the nonlinearmodel for every frame, it can be said that the time-varying linearsystem, W_(m), of the model is adapted every frame, and the model isfurther adapted by changes to the estimated model parameter tensor, Θ,for each iteration or control sample. In other words, adaptation of themodel is bifurcated into faster and slower portions—a fast portion basedon adaptation of Θ and a slower portion based on adaptation of thetime-varying linear system, W_(m). The illustrated estimation law isbased on the input regressor, Ø, and the adaptation gain, Γ, thoughother estimation laws can be functions of similar or different values(e.g., not including the adaptation gain, Γ, and/or being a function ofa filtered version of the input regressor, Ø).

Integrating the illustrated estimation law gives the estimated modelparameter tensor, Θ, and once this tensor is estimated, it can be passedto the model 4608, which has two parts: a control portion fordetermining u_(se) and an estimation portion for determining y_(est_se),both of which are functions of the estimated model parameter tensor, Θ.Both can also be based on versions of the input regressor or a filteredversion thereof, such as, but not limited to, ω and ψ. As shown, theestimation portion of the model 4608B is also a function of thetime-varying linear system, W_(m), of the linearized version of themodel, however, an alternative sees the control portion depending on thetime-varying linear system, W_(m). Both portions of the model can beparameterized or parametric. These two portions of the model exhibitduality as they are related through the same model 4608. The control lawmodule is also referred to earlier in this disclosure as a sub-engine,and various sub-engines present differing uses of the model 4608, thoughultimately, they all rely on similar inputs to those shown in thisillustration, and each sub-engine typically produces a possible controlsignal, u_(se), and an estimated system output, y_(est_se).

Both portions or forms of the model 4608A and 4608B “test” the estimatedmodel parameter tensor, Θ, to see how well the estimate performs. Thisoperation in the control law module also produces (1) the possiblecontrol signal, u_(se), which is passed to the second form of the model4608B, and (2) the estimate of the system response/measurement,y_(est_se), which may u_(se) the time-varying linear system, W_(m), insome variations, that the frame resynthesizer 4602 or designer hasselected for the entire frame.

These two outputs of the model 4608 are passed to the selector module4610, which selects a best one or a best combination of u_(se) from thevarious combinations of estimation law modules and control law modules(only one combination is shown) to produce the control, u_(c)m, for theiteration or control sample.

The estimation law module 4606 and control law module loop 4608 in thisfashion for a number of iterations or control samples to “adapt” theestimated model parameter tensor, Θ (or adapt the linearized form of themodel) within the current frame. As the adapted model converges on thenonlinear behavior of the system, the estimated model parameter tensor,Θ, will become nearly constant (i.e., see little Δ as additionaliterations occur) as will the time-varying linear system, W_(m), thatdepends on the estimated model parameter tensor, Θ. At the end of aframe, the frame resynthesizer (or the designer's lookup table)calculates a new structure of the time-varying linear system, W_(m), forthe linearized form of the nonlinear model, and passes the new structureto the model 4608 to start another series of adaptations of theestimated model parameter, Θ.

Operations of the adaptive engine 4600 can also be bifurcated between aprocessor and an FPGA. In particular, the processor can compute thestructure of the time-varying linear system, W_(m), once per frame orpre-process various structures for various expected sets of inputs. TheFPGA, with its lower latency, can attend to sample-by-sample (real time)calculations of ê, J, Θ, u_(se), and/or y_(est_se), for each iterationor control sample. In this way, the whole of the adaption engine 4600can be bifurcated across a processor and an FPGA, or similar components.

Details of Control Law Modules/Sub-Engines

The following sections describe details of various exemplary control lawmodules or sub-engines, though this list is not limiting. One or more ofthese sub-engines can be implemented independently from the othersub-engines, and in some embodiments even stand on their own independentfrom the rest of the adaptive engine. For instance, each sub-engine canbe implemented without the herein disclosed estimation law modules orselector module. In other embodiments, less than all of the hereindisclosed sub-engines need be implemented. For instance, what will becalled a TLMC (or Lyapunov) sub-engine uses the Lyapunov framework whichleads to stable outputs in fast dynamic situations and those where largeamounts of adaptation are needed. In other words, the TLMC creates astable control law by ensuring that sensitivity functions do not exhibitabrupt variations and are stable by construction. For these cases, theTLMC sub-engine can be implemented, selected, or given priority in theblending of possible control signals, u_(se). However, this TLMCsub-engine can be slow to converge and is not particularly well-suitedfor unstable zero dynamics. Accordingly, a second sub-engine or TARC,can be implemented, selected, or given priority in the blending ofpossible control signals, u_(se), as this sub-engine quickly convergesto a target metric and/or optimize an amount of energy used (e.g., aminimum rail voltage to achieve a setpoint). The TARC creates fast andstable control laws by reformulation of the control problem such thatsome quantities can be pre-computed on a CPU leading to faster and morerobust real-time operation. Additionally, the TARC allows a designer tospecify the speed and amount of stability desired in addition tocharacterizing the control actuators that are to do the heavy liftingand the ones that are to do lesser lifting. So, for instance, theselector module may choose between and possibly blend possible controlsignals, u_(se), from a TLMC and TARC sub-engine. An embodiment usingthese two sub-engines would provide some coverage for stable andunstable zero-dynamics without any other sub-engines.

However, the TARC sub-engine can become unstable when the adaptiveengine is perturbed and/or increases or decreases of the control,u_(out), are too granular to achieve performance that has “converged”and thus the control, u_(out), becomes oscillatory. Examples ofperturbations include, but are not limited to, a limiting loop, or asmall change in plasma process chemistry). Oscillatory action may happenwhere the convergence is too large, but the error from a targetparameter is too small to merely increase the adaptation gain—the resultbeing an oscillatory control, u_(out). So, the TARC can be implemented,selected or have the most influence on the control, u_(out), for stableand un-stable zero-dynamics, and the TLMC can be implemented, selectedor have the most influence on the control, u_(out), when stable adaptionis desired (at the sacrifice of convergence speed).

Yet, neither of these sub-engines are well-suited for unstablezero-dynamics, where higher speeds and smaller unknown disturbancerejection is preferred. For these situations, a third sub-engine, the L1sub-engine, may be implemented, selected or have priority in a blendingof possible control signals, u_(se). The L1 sub-engine is configured toprovide a fast and robust possible control signal, u_(se), withoutoutput chattering by using a sliding mode predictor in conjunction withcarrying adaptation based on how different the prediction (not theestimate) is from a smoothed system output measurement, y_(meas).

However, all of the first three sub-engines suffer from slower speeds insituations where expert rules exist (e.g., tricks of the trade picked upthrough years of trial and error), so a fourth sub-engine, the adaptiveproportional-integral-derivative (PID), can be implemented, selected orhave the most influence on the control, u_(out), in these situationsusing known PID rules. The PID sub-engine generalizes and formats theestimation laws so that PID rules can be applied to the outputs of theestimation law modules.

But, where there is not a-priori knowledge about the system dynamics andwhere large disturbances exist (e.g., an abrupt change in processchemistry or changing chamber pressure, gas flow, or thermal conditionsor anything that would cause a large change in plasma impedance), orwhere the system is oscillatory, a fifth sub-engine, the ATIMCsub-engine can be implemented, selected or have the most influence onthe control, u_(out). The ATIMC sub-engine creates a control law indifferent parts by subtracting specific effects of disturbances,nonlinearities, dither, and noise in a compartmentalized manner ratherthan lumping these together.

However, there are operating regions where none-of-the-above sub-enginesare ideal, or outlier cases where superior empirically derived controlrules exist, and for these a sixth sub-engine, or ATFC sub-engine can beimplemented, selected or given priority in the possible control signals,u_(se), blending. The ATFC sub-engine uses fuzzy logic design rules thatare qualitative rather than quantitative.

One should note that nothing in the literature describes how to carryout any of these sub-engines for MIMO and nonlinear systems or even SISOlinear systems in a way that actually fits in real-time (e.g., ≤250n_(s)) systems with minimal resource consumption.

The TLMC or Lyapunov Sub-Engine

FIG. 10A shows an embodiment of an adaptive engine focusing on detailsof a Lyapunov control law module or Lyapunov sub-engine (also called aTLMC control law module or sub-engine). The adaptive engine 1000includes at least one estimation law module 1002, a control law moduleor sub engine 1005, and a selector module 1008. As with previousadaptive engines discussed herein, the estimation law module 1002 takesan input regressor, Ø, and estimates a model parameter tensor, Θ, for anonlinear model of the actuators and/or system (e.g., a plasmaprocessing system). The estimated model parameter tensor, Θ, isdetermined for most estimation laws using at least a portion of theinput regressor, Ø, and an estimation error, ê, or cost function, J,either of which can be written in various forms, but typically comprisesome combination of two or more of the measured system output, y_(meas),an estimated system output for a given control law module, y_(est_se),and a reference signal, r. Typically, the measured system output,y_(meas), and the estimated system output, y_(est_se), are for aprevious iteration and thus in some cases can be written asy_(meas)(k−1) and y_(est_se)(k−1). Said another way, each estimation lawmodule estimates an estimated model parameter tensor, Θ, that minimizesan estimation error, ê, or cost function, J.

The estimated model parameter tensor, Θ, is then used by the nonlinearmodel in the Lyapunov sub-engine 1005 to generate a possible controlsignal, u_(se), and to estimate an estimated system output, y_(est_se),both of which are then used by the selector module 1008 to select a bestone or best combination of possible control signals as the control,u_(out). Although only a single estimation law module 1002, and a singlecorresponding possible control signal, u_(se), and estimated systemoutput, y_(est_se), are shown, the Lyapunov sub-engine 1005 can takeestimated model parameter tensors, Θ, from multiple estimation lawmodules 1002, and produce multiple pairs of u_(se) and y_(est_se) (onefor each estimation law module 1002).

The estimated model parameter tensor, Θ, is passed to the control lawmodule or sub engine 1005, in this case, the Lyapunov sub-engine 1005,which passes the estimated model parameter tensor, Θ, through anonlinear model of the system and/or actuators to produce a possiblecontrol signal, u_(se), and an estimated system output, y_(est_se).Specifically, a control portion 1016 of the nonlinear model produces thepossible control signal, u_(se), and an estimation portion 1018 of thenonlinear model produces the estimated system output, y_(est_se).

More particularly, the Lyapunov sub engine 1005 takes the (1) inputregressor, Ø, which may include at least the reference signal, r, andthe control from the previous iteration, u_(out), and (2) the estimatedmodel parameter tensor, Θ, and performs a tensor multiplication 1012 onthese inputs. More specifically, the tensor multiplication 1012implements a version of the first control law where the input regressor,Ø, is not modified before tensor multiplication 1012:

u _(se)=θ·Ø  (Control Law 1A)

However, and as will be discussed in depth later, the Control Law 1Ausing w instead of Ø can be used where the sub-engine 1005 of FIG. 10Bis implemented and some modification of Ø to get ω occurs. Morespecifically, in Control Law 1A, ω overlaps with but is not identical toØ. In particular, ω is a concatenation that can include some form ofu_(out) k−1, y_(meas), and r (i.e., often components of Ø). Forinstance, one or more of these values can be filtered before beingconcatenated into w. For instance, w may equal [u_(d), y_(d), y_(meas),r] where u_(d) and y_(d) are filtered or smoothed versions of u_(out)and y_(meas), respectively. See FIG. 10B for a more specificimplementation of ω replacing Ø.

The input regressor, Ø, can include inputs that correspond to the outputparameters to be controlled (and thus the estimated model parametertensor Θ). These inputs can include, but are not limited to, thereference signal, r, the measured system output, y_(meas), the controlfrom the previous iteration, u_(out), and in some cases the estimatedsystem output, y_(est_se), for the Lyapunov sub-engine 1005. For Model1, the control portion 1016 multiplies the input regressor, Ø, includingthe control signal from the previous iteration, u_(out), and theestimated model parameter tensor, Θ. For instance, if the inputregressor, Ø, includes r and y_(meas), then the estimated modelparameter tensor, Θ, will include Ø values for r and y_(meas). Morespecifically, if Ø=[r, y_(meas), u_(out)], then Θ=[Θ_(r), Θ_(ymeas),Θ_(uout)]. Accordingly, for this example, the possible control signalwould be u_(se)=θØ=[r, y_(meas), u_(out)] [Θ_(r), Θ_(ymeas),Θ_(uout)]=rΘ_(r)+y_(meas)Θ_(ymeas)+u_(out)Θ_(uout) and this matrixmultiplication takes place in the tensor multiply 1012. The estimationportion 1018 multiplies the time-varying linear system, W_(m), and theoutput of the control portion, the possible control signal, u_(se).Where Model 2 is used, the tensor multiplication 1012 sees the controlportion 1016 multiply the time-varying linear system, W_(m), by thetotal estimated system output, y_(est_out), or the measured systemoutput, y_(meas). Similarly, the estimation portion 1018 multiplies Θand Ø.

One might recognize that Control Law 1A is the control portion of Model1 referred to earlier. An example control law is not presented tocorrespond to Model 2, but it can be said that the Lyapunov sub-engine1005 can implement Models 1 or 2 without other modifications, whereassubsequent sub-engines may implement either model, but withmodifications to achieve different control goals.

Once the control portion 1016 has calculated u_(se), it can u_(se) thepossible control signal, u_(se), to calculate the estimated systemoutput, y_(est_se) via the estimation portion 1018 of the nonlinearmodel. In this embodiment, the tensor multiply 1012 can be thought of asimplementing the two forms of the model (control and estimation forms)to test the guesses for Θ, which produces u_(se) and y_(est_se) for thisiteration. The resulting u_(se) and y_(est_se) can be passed to theselector module 1008, that provides a total system control, or control,u_(out), as a best of the possible control signals, u_(se), or a bestcombination or blending of two or more of the possible control signals,u_(se) (e.g., a weighted average, multiplication, or summation). Thiscalculation can be based on the estimated system outputs, y_(est_se),from the Lyapunov sub-engine 1005 and all other sub-engines. Forinstance, a total estimated system output y_(est_out) can be calculatedfor various combinations or topologies of y_(est_se), and the topologyleading to a total estimated system output y_(est_out) that is closestto r or y_(meas) (i.e., a smallest estimated system error, ê_(out), orestimated system cost function, J_(out).) is used to select or combinepossible control signals, u_(se).

Thus completes a single iteration of sub-engine 1005 operation. Thecontrol, u_(out) can be fed back as part of the next input regressor, Ø,and the time-varying linear system, W_(m), can be adapted via changing Θover multiple iterations in this manner until W_(m) converges on theactual nonlinear system behavior (i.e., the unknown nonlinear portion ofW_(m) is minimized). This can continue until a new frame, at which pointa new structure of the time-varying linear system, W_(m), is provided tothe estimation law module 1002 and/or the tensor multiply 1012, andadaptation of Θ within this next frame begins.

Although not explicitly shown, the control signal u_(out) is fed back tothe input regressor, Ø, and may be provided to the estimation law module1002 and/or the sub-engine 1005. The estimated system output,y_(est_se), can also be passed back to the estimation law module 1002for u_(se) in determining the next iteration of Θ. One or both of thesecan be stored in memory along the way, such as a TSP-RAM.

Because a generator or match or any other system to be controlled mayinclude nonlinearities, for instance associated with analog to digitalconversion or digital to analog conversion (e.g., quantization effects)and hardware actuator nonlinearities (e.g., slew rate, saturation,windup, deadtime, dead zone, hysteresis, etc.), to name just a fewexamples, the Lyapunov sub-engine 1005 can optionally include anonlinear transfer function(s) 1013. When 1013 is implemented, thetensor multiply 1012 can produce what will be called ideal or desiredoutputs, u_(desired) and y_(est_ideal), which will then be transformedinto u_(se) and y_(est_se) in the nonlinear transfer function(s) 1013.The hardware nonlinearities can be characterized during the design stageand a parameterized dynamic model of these nonlinearities, and theireffects can be hardwired or programmed into the nonlinear transferfunction(s) 1013, such that:

u _(se)≙(u _(desired) +f(nonlinear))g(nonlinear)  (Equation 8)

y _(est_se)≙(y _(est_ideal) +f(nonlinear))g(nonlinear)  (Equation 9)

While this embodiment implements both the control and estimationportions of the nonlinear model in the tensor multiply 1012, in analternative embodiment, the estimation portion of the nonlinear modelcan be implemented in the estimation law module 1002. In this case,y_(est_se) or y_(est_ideal) will be calculated in the estimation lawmodule 1002 based on the input regressor, Ø, the estimated systemparameter tensor, Θ, and a previous iteration of the possible controlsignal, u_(se). The estimated system output, y_(est_se), is then passedto the selector module 1008 as described above, or the y_(est_ideal) isthen passed to the nonlinear transfer function(s) 1013 as shown in FIG.10A and as described above. For further details of this variation wherethe estimation portion of the model is used by the estimation law module1002, refer to FIGS. 5B and 8B.

To further improve accuracy and the speed of convergence, FIG. 10Bpresents a variation of FIG. 10A where the derivative of the estimatedmodel parameter tensor, Θ, is also used. In particular, the controlportion of the nonlinear model, or Control Law 1A, can be written interms of Θ and its derivative as Control Law 1B as follows:

u _(se)=[θ,{dot over (θ)}][Ω]=θω+{dot over (θ)}χ  (Control Law 1B)

And the estimation law module 1002 can calculate both the estimatedmodel parameter tensor, θ, and its derivative, θ′. These can both bepassed to the tensor multiply 1012. However, instead of the inputregressor, Ø, being the other input to the tensor multiply 1012, tensorΩ is the second input in the tensor multiply 1012. Said another way, thetensor multiply 1012 performs u_(se)=[θ,θ′ ]·Ω. To get to Control Law1B, or the control portion of the nonlinear model, the input regressor,Ø, is split up and the system output measurement, y_(meas), and thecontrol signal from a previous iteration, u_(out), are passed throughsmoothing filters 1020. The smoothed versions of y_(meas) and u_(out)can be referred to as y_(d) and u_(d). The smoothing filters 1020 canapply, for instance, a minimum group/phase delay persistent excitation,which can produce noise free signals and/or derivatives of the inputs tothe filters 1020. The reference signal, r, and the non-smoothed systemoutput, y_(meas), can then be passed to a tensor concatenation 1022along with the smoothed values, y_(d) and u_(d), to produce aconcatenated tensor ω (where ω=[r, y_(meas), y_(d), u_(d)]). Theconcatenated tensor ω can be passed through another set of smoothingfilters 1024 (which can be the same as the smoothing filters 1020 insome embodiments), to obtain χ. The χ tensor can take the filtered valueof ω and insert 0's where appropriate. This can be understood as theprocess having a relative degree when discussing single-in-single-out(SISO) transfer functions. Subsequently, ω and χ can be concatenated intensor concatenation 1026, and the tensor multiply 1012 performs theControl Law 1B or u_(se)=θω+{dot over (θ)}χ. In other words, regardlessof the relative degree of the system, its nonlinearities, and/or itsMIMO status, this u_(se) of χ allows generic application. Once the W_(m)structure is selected for a frame, the χ tensor takes on the filteredvalues from ω and depending on the relative order, fills out someentries with 0's. The remainder of each iteration is carried out asdescribed relative to FIG. 10A.

To enhance the u_(se) of processing resources, the estimation law module1002 and parts of the sub-engine 1005 can operate in parallel. Forinstance, determination of the estimated model parameter tensor and itsderivative, [θ,{dot over (θ)}], can be carried out in parallel todetermine the ω, χ, and Ω tensors. More specifically, the sub-engine1005 in a first FPGA cycle can calculate ω, while the estimation lawmodule 1002 begins to determine the estimated model parameter tensor andits derivative, [θ,{dot over (θ)}]. In a second FPGA cycle, thesub-engine 1005 can determine χ and Ω while the estimation law module1002 finishes determining the estimated model parameter tensor and itsderivative, [θ,{dot over (θ)}]. In a third FPGA cycle, the tensormultiply 1012 can multiply the estimated model parameter tensor and itsderivative, [θ,{dot over (θ)}], and Q to produce the u_(desired) and they_(est_ideal). In a fourth FPGA cycle, the nonlinear transfer functions1013 can convert the u_(desired) and the y_(est_ideal) to the u_(se) andthe y_(est_se), and in a fifth FPGA cycle the selector module 1008 canproduce the control signal, u_(out), from the outputs of the multiplesub-engines 1005. This cycle rate can lead to a 6× oversampling/resourcesharing/streaming factor and between 5-25 MHz control rate in someembodiments. However, slower control rates, such as lower than 5 MHz canachieve an 8× to 32× oversampling/resource sharing/streaming factor.These lower control rates and higher oversampling factors can lowerhardware usage (e.g., as low as 5% FPGA usage).

FIG. 47 illustrates a method of operating a sub-engine such as theLyapunov sub-engine. The method 4700 comprises receiving an inputregressor, Ø (Block 4702), and an estimated model parameter tensor, Θ(Block 4704), for a nonlinear model of the one or more actuators and/orthe power system controlled by the one or more actuators. The inputregressor, Ø, can include inputs that correspond to the outputparameters to be controlled (and thus the estimated model parametertensor Θ). These inputs can include, but are not limited to, thereference signal, r, the measured system output, y_(meas), the controlfrom the previous iteration, u_(out), and in some cases the estimatedsystem output for the sub-engine, y_(est_se). The estimated modelparameter tensor, Θ, may be estimated, for instance by one of theestimation law modules previously discussed, or may be accessed from anempirically derived lookup table. For instance, if the Lyapunovsub-engine operates independently to control one or more actuators, anestimation law module may not be available, in which case, the estimatedmodel parameter tensors, Θ, can be found via experimentation and storedin a lookup table that the Lyapunov sub-engine can access based on oneor more of a reference signal, r, a control, u_(out), from a previousiteration, and measurements of the system output, y_(meas), from aprevious iteration. The method 4700 further comprises receiving astructure of a time-varying linear system, W_(m) (Block 4706) that ispart of a nonlinear model. The time-varying linear system, W_(m), canhave a structure that is pre-calculated in a frame resynthesizer andthen newly passed to the Lyapunov sub-engine every frame or can beaccessed from an empirically derived lookup table at every frame. Thetime-varying linear system, W_(m), can depend on the estimated modelparameter tensor, Θ, and thus can change or adapt every iteration orcontrol sample. However, it can have a structure that remains the samethrough a given frame, but changes from frame to frame. Thus, theframe-to-frame changes in structure account for large changes in thenonlinear system behavior, while adjustments to Θ and hence thetime-varying linear system, W_(m), within a frame, account for smallnonlinear system behaviors. The method 4700 can optionally performcertain filtering operations on one or more components of the inputregressor, Ø (optional Block 4708) and concatenate parts of the inputregressor with the new filtered tensors to form a modified regressor, ω(optional Block 4710). These optional steps can be embodied by thecomponents 1020 and 1022, respectively, seen in FIG. 10B. The modifiedregressor, ω, can optionally be further filtered to form a doublymodified regressor, χ, where 0's can be inserted into χ, whereappropriate depending on the relative order of W_(m) (optional Block4712). The modified regressor, ω, and the doubly modified regressor, χ,can be concatenated, to form a final tensor, Ω (optional Block 4714).These last two optional blocks can be embodied by the components 1024and 1026, respectively, see in FIG. 10B. These optional blocks allow themethod 4700 to by applied generically to systems regardless of theirrelative degree, nonlinearities, and/or MIMO status. To either the inputregressor, Ø, or the final tensor, Ω, the method 4700 can apply acontrol portion of the nonlinear model by tensor multiplication of theestimated model parameter tensor, Θ, and the input regressor, Ø (oroptionally the final tensor, Ω) (Block 4716). This calculates a possiblecontrol signal, u_(se). The method 4700 can also apply an estimationportion of the nonlinear model by using the possible control signal,u_(se), and the estimated model parameter tensor, Θ, as inputs to thetime-varying linear system, W_(m), to estimate an estimated systemoutput, y_(est_se) (Block 4718). The estimated system output,y_(est_se), can then be used to determine how the possible controlsignal, u_(se), influences a control output, u_(out), (Block 4720),which is configured for controlling the one or more actuators and/or thesystem controlled by the one or more actuators (Block 4722).

Although not illustrated, the Lyapunov sub-engine can operate as astandalone controller. In such an embodiment, the estimation law modulescan be replaced by an empirically derived lookup table for the estimatedmodel parameter tensor, Θ. More specifically, a lookup table can beempirically formed as a mapping between (1) y_(meas) and u_(out) from areference/calibration system and (2) estimated model parameter tensors,Θ. During operation of the Lyapunov sub-engine as a standalonecontroller, a control, u_(out), can be provided to the one or moreactuators, and measurements, y_(meas), can be taken from the one or moreactuators and/or system. These can then be used to select an estimatedmodel parameter tensor, Θ, from the lookup table, and then provided tothe Lyapunov standalone controller to determine what will be called acontrol signal, u_(out). This control signal, u_(out), can be providedto the one or more actuators. Alternatively, the Lyapunov standalonecontroller can produce a string of possible control signals, u_(se), andform a control, u_(out), as a combination of the string. For instance, aweighted average of the possible control signals, u_(se), can be used tocalculate the control, u_(out), although other methods of combining thestring can also be implemented. In some embodiments, the combination maybe based on estimated system outputs, y_(est_se), for each of thepossible control signals, u_(se), similar to the way in which a topologyis selected in the selector and combiner mentioned earlier. Theseestimated system outputs, y_(est_se), can be found via an estimationportion of the nonlinear model, for instance, using Model 1:

y _(est_se) =W _(m) {u _(se),Θ}

Where the estimated model parameter tensor, Θ, is found in the lookuptable based on the measured system output, y_(meas), and the control,u_(out), both from a previous iteration.

The Tensor Adaptive Tracking and Regulation Control (TARC) Sub-Engine

The Lyapunov sub-engine (i.e., the TLMC sub-engine described above) isdesigned to operate in a multitude of conditions and with relativelylarge adaptation gains Γ, Γ₁, Γ₂, etc., recalling that F is theadaptation gain tensor. In some circumstances, however, the Lyapunovsub-engine may not be the most optimal for adaptive control. Forexample, the Lyapunov sub-engine may not be the most optimal when thenon-linear system being controlled has unstable zero dynamics (e.g.,non-minimum phase for a single input single output or SISO linearsystem). Aspects of the present disclosure are directed to a control lawsub-engine (herein referred to as the Tensor Adaptive Tracking andRegulation Control or TARC sub-engine) that is configured to work inconjunction with the Lyapunov control law sub-engine and any of theother control law sub-engines described herein to optimize the controlsignal(s) provided to the actuator(s) of the non-linear system beingcontrolled. In some embodiments, the TARC sub-engine can also operateindependent of any other sub-engines and may therefore be referred to asa TARC controller.

By supporting parallel processing, the TARC control law sub-engine isdesigned to optimize the use of the Tensor Signal Processing (TSP)hardware resources of the adaptive engine. Additionally, oralternatively, the TARC control law sub-engine also facilitates in theuse of internal model control (IMC) principles. Broadly, IMC refers to acontrol design where the reverted input/output (I/O) model of theprocess/system being controlled is included within the controller. Saidanother way, IMC systems are characterized by a control deviceconsisting of the controller and of a simulation of the process beingcontrolled (i.e., the internal model). The internal model computes thedifference between the outputs of the process and of the internal model,where the difference represents the effect of disturbances and/or of amismatch of the internal model. The disclosed TARC control lawsub-engine may facilitate in smoother waveforms and/or faster settlingtimes, as compared to the prior art, through the use of an IMC scheme,an adaptive inverse control scheme, or a combination thereof.

In some embodiments, the TARC control sub-engine is configured to manageboth desired process performance and efficiency, for instance, when therail and drive frequency are being controlled simultaneously. In suchcases, the TARC control sub-engine is designed to prevent errortransmission buildup by incorporating a matrix (or tensor), where thematrix is used to place weights on the control signals whose amplitudesare to be minimized. In some aspects, the TARC control law sub-engineenables the use of weighted control signals in a manner similar toLinear Quadratic Control (LQC) schemes.

In some embodiments, the adaptive engine may be augmented with the TARCand TLMC control law sub-engines, as well as other control lawsub-engines described later in the disclosure. In this way, the adaptiveengine may select the most optimal control law sub-engine for aparticular situation (or the most optimal combination of control lawsub-engines). In some examples, the adaptive engine compares theestimated error (or estimation error) associated with the differentcontrol law sub-engines to determine which of the control lawsub-engines should be used. For instance, the adaptive engine may selectthe possible control signal produced by one of the plurality of controllaw sub-engines based on determining that the control law sub-engine isassociated with the lowest estimation error (i.e., highest estimationaccuracy). Said another way, the adaptive engine (e.g., a selectormodule) may select a one or combination of possible control signals,u_(se), that lead to a control, u_(out), that causes a measured systemoutput, y_(meas), that is close to the total estimated system output,y_(est_out), or the reference signal, r. This may involve an error orcost function that compares the measured system output, y_(meas), for aprevious iteration, or the reference signal, r, to the total estimatedsystem outputs, y_(est_out), calculated for various possible topologies.More specifically, the TSD 518 may analyze a cost function, such asEquation 4, to select an optimal possible control signal, u_(se), orcombination of possible control signals, u_(se) (in the form of atopology for combining the possible control signals).

In the case of stable zero-dynamics, the TARC control law sub-engineattempts to achieve the desired performance in the shortest timepossible and/or with minimal control efforts (e.g., minimal/optimizedenergy use, minimal/optimal use of controller hardware resources, toname two non-limiting examples). In some cases, for instance, when theTARC control law sub-engine is predicted to cause stability issues, theTLMC control law sub-engine (or any other control law sub-engine) maytake over. Once the predictions associated with the TARC control lawsub-engine stabilize, the adaptive engine may switch from the TLMC backto using the possible control signal(s) provided by the TARC to controlthe non-linear system.

As described in further detail below, the TARC control law sub-engineallows for a high level of parallelization by deploying multiple controllaw modules on parallel paths. The TARC control law sub-engine comprisestwo or more control law modules (e.g., an adaptive inverse laws or AILcontrol law module, an eigen control law module, a penalty control lawmodule) that can be implemented in parallel, where the parallelimplementation enables one or more of oversampling, resourcesharing/streaming, and pipelining. Such a design may serve to optimizehardware resource usage. In some examples, several FPGA clock cycles maybe used to collect data which is then passed as a single stream of data,herein referred to as “resource streaming”. In some aspects, this servesto reduce the length of the critical path of the system, which may ormay not be at the cost of FPGA clock cycles. However, since several FPGAclock cycles can usually be fit within one control clock cycle, such adesign has negligible effect on the control output speed.

FIG. 11A depicts an example of an adaptive engine 1100, according tovarious aspects of the disclosure. As seen, the adaptive engine 1100comprises an estimation law module 1104 (also referred to as FELB 1104)and a control law sub-engine 1106, where the control law sub-engine 1106includes a plurality of control law modules. In this example, thecontrol law sub-engine 1106 comprises an Adaptive Inversion Laws (AIL)module 1114 and an Adaptive Tensor of Matrices Laws (ATML) module 1166,where the ATML module 1166 comprises an Eigen Laws (EL) module 1124 anda Penalty Laws (PL) module 1134. It is contemplated that the AIL module1114, the EL module 1124, and the PL module 1134 may be referred to asthe control law modules of the control law sub-engine 1106. The controllaw sub-engine 1106 further comprises a control selector/combiner (CSC)1107, where the CSC 1107 is configured to receive a possible controlsignal from each of the control law modules and output a final possiblecontrol signal (e.g., u_(se)) for the adaptive engine 1100. The adaptiveengine 1100 further includes a selector module 1108, where the selectormodule 1108 includes another control selector/combiner (CSC) 1116 and anoptional topology selector and designer (TSD) 1118. The CSC 1116 and theTSD 1118 may be similar or substantially similar to the CSC 516 and theTSD 518 previously described in relation to FIG. 5 .

Similar to some of the other estimation law modules (or FELBs) describedherein, the FELB 1104 is configured to receive an input regressor, applyone or more estimation laws to the input regressor, and produce one ormore sets of estimated parameter tensors, Θ, for a non-linear (NL) modelof the one or more actuators and/or the system controlled by the one ormore actuators. In some cases, the input regressor comprises one or moreof (1) a setpoint stream (also referred to as a reference signal), r,(2) a system output measurement, y_(meas), and (3) a control output,u_(out_k−1), from a previous iteration. In some examples, the estimationportion 808 of the nonlinear model (which is a parameterized nonlinearmodel) is stored and/or executed on the FELB 1104, as depicted in FIG.11B. In other cases, the estimation portion 808 is stored and/orexecuted at the control law sub-engine. In either case, the estimationportion 808 is configured to produce a plurality of possible estimatedsystem outputs, y_(est_SE), based upon a control input. The controlinput(s) used to produce the possible estimated system output(s) may bebased in part on the location of the estimation portion 808. In someinstances, the control input fed to the estimation portion 808 includesa previous iteration of the possible control signal, u_(SE_k−1) (oru_(se_k−1)), for the adaptive engine 1100. In some other cases, thecontrol input fed to the estimation portion 808 includes a currentiteration, u_(SE_k), of the possible control signal. In yet other cases,the control input fed to the estimation portion 808 includes an actualcontrol signal (u_(out_k−1)) for a previous iteration, i.e., theactual/output control signal applied to the one or more actuators and/orthe system controlled by the one or more actuators. In some cases, thisactual/output control signal is the final control output signal computedby the selector module 1108.

As seen in FIG. 11A, the FELB outputs a plurality of estimated parametertensors [Θ], one for each of the AIL module 1114, the EL module 1124,and the PL module 1134. In some examples, the FELB 1104 may output asingle estimated parameter tensor that is fed to each of the threecontrol law modules. In some instances, the plurality of estimatedparameter tensors [Θ] may be stored in tensor memory 1152 of theadaptive engine. The control law modules are configured to output apossible control to the CSC 1107, which then outputs the possiblecontrol signal (u_(SE)) and the estimated system output (y_(est_SE))corresponding to the adaptive engine 1100 to the selector module 1108.The selector module 1108 also receives one or more other possiblecontrol signals (u_(SE1), u_(SE2), etc.) and estimated system outputs(y_(est_SE1), y_(est_SE2), etc.) from one or more other controlsub-engines (or control law modules). In some cases, the CSC 1107outputs one of, or a combination of, the possible control signalsreceived from the control modules of the control law sub-engine 1106. Asseen, the CSC 1107 receives a possible control signal (e.g., u_(SE_AIL),u_(SE_EL), u_(SE_PL)) and an estimated system output (e.g.,y_(est_SE_AIL), y_(est_SE_PL), y_(est_SE_EL)) from each of the AILcontrol law module 1114, the EL control law module 1124, and the PLcontrol law module 1134 and outputs a single u_(SE) and y_(est_SE) tothe selector module 1108. In other words, the u_(SE) and y_(est_SE)provided to the selector module 1108 may be one of the possible controlsignals and estimated system outputs, or alternatively, a combination ofthe possible control signals and estimated system outputs received bythe CSC 1107.

In an embodiment, the AIL 1114, the Eigen Laws 1124, and the PenaltyLaws 1134, can produce the estimated system output (e.g.,y_(est_SE_AIL), y_(est_SE_PL), y_(est_SE_EL)) using an estimationportion of the nonlinear model. More specifically, the system model ornonlinear model can be provided with a control portion, for generatingpossible control signals, u_(se), and an estimation portion forestimating estimated system outputs, y_(est_se). A time-varying linearsystem, W_(m), can make up a foundation of either the estimation portionor the control portion, and can be bifurcated or split into a sum of alinear and a nonlinear portion and the control timeline can be splitinto frames of differing lengths (or number of control samples oradaptation iterations) with some processing of the nonlinear modeloccurring on a CPU or other slower resource and real-time aspects of thenonlinear model occurring on an FPGA or other faster resource. A currentframe can be supplied with a structure of the time-varying linearsystem, W_(m). As noted relative to FIG. 43 , the nonlinear portion ofthe time-varying linear system, W_(m), is effectively an unknown errorand thus not used or considered in the processing (other than in attemptto minimize this error). The structure of the time-varying linearsystem, W_(m), can be pre-processed, for instance on a CPU, though itcan also be accessed from an empirically-derived lookup table. Thestructure of the time-varying linear system, W_(m), remains constantthrough the current frame. Yet, since the time-varying linear system,W_(m), is also dependent on the estimated model parameter tensor, Θ, theestimation portion of the nonlinear model adapts within a frame as Θchanges in the FELB 1104 (as the adaptive engine modifies Θ to minimizean error relative to measured system behavior). This can involvecalculating an estimation error, ê, or cost function, J, based on two ormore of (1) measured system outputs, y_(meas), from a previousiteration, (2) estimated system outputs, y_(est_se), from a previousiteration, and (3) reference signal, r. Adaption can then involveapplying an estimation law to at least the reference signal, r, and theestimation error, ê, or cost function, J, to estimate an estimated modelparameter tensor, Θ. The estimated model parameter tensors, Θ, can thenbe tested in the AIL 1114, Eigen Laws 1124, and the Penalty Laws 1134,and adaptation can continue through the entirety of the frame, and inturn, W_(m), is adapted throughout the frame (or until convergence isachieved). Once a frame is complete the method selects a next frame anda new structure of the time-varying linear system, W_(m), is providedinto the model and adaptation of the estimated model parameter tensor,Θ, is carried out through this next frame until convergence. As notedearlier, the structure of the time-varying linear system, W_(m), caninclude the structure of the A, B, and C matrices that are part of thesystem of equations making up W_(m).

Turning now to FIG. 11B, which illustrates a detailed view of the AILcontrol law module 1114, in accordance with one or more implementations.As seen, the AIL control law module 1114 comprises filters 1181, wherethe filters 1181 include smoothing filters 1182 and smoothing inversefilters 1183. The AIL control law module 1114 further comprises atransformation module 1188 and a tensor multiply module 1112. In thisexample, the FELB 1104 comprises the estimation portion 808 (which canimplement the time-varying linear system, W_(m)). As seen, the FELB 1104is configured to receive an input regressor, where the input regressorincludes (1) the setpoint stream, r, (2) the system output measurement,y_(meas), (3) an error signal, e, where the error signal is based on adifference between the setpoint stream and the system outputmeasurement, and/or (4) a possible control signal, u_(SE_AIL), for theAIL control law module 1114. While not necessary, the possible controlsignal, u_(SE_AIL), may correspond to a possible control signal from acurrent control iteration. The FELB 1104 is configured to calculate afirst set of estimated parameter tensors, [Θ], for the nonlinear modelbased on applying one or more estimation laws to the input regressor. Inthis example, the FELB 1104 provides the first set of estimatedparameter tensors [Θ] to the tensor multiply module 1112.

The tensor multiply module 1112 is electronically, communicatively,and/or logistically coupled to the filters 1181, the memory 1152, thetransformation module 1188, and the FELB 1104. Further, the tensormultiply module 1112 is configured to receive a tensor (A_(CL)), wherethe A_(CL) tensor is the tensor of time-varying linear systemrepresentation of the desired arbitrary non-linear waveform desired bythe user as the output of the non-linear/chaotic generator/match/chamberplasma system. Additionally, or alternatively, the tensor multiplymodule 1112 also receives an internal model (Q_(m)), where the internalmodel, Q_(m), represents the desired/reference plasma processperformance. In some examples, Q_(m) may be the filtered version ofW_(m). In some cases, the tensor multiply module 1112 receives one ormore of the A_(CL) and the Q_(m) from the FELB 1104 (or anothercomponent of the adaptive engine 1100). The smoothing filters 1182 andthe smoothing inverse filters 1183 are configured to receive the controloutput, u_(out_k−1), from the previous iteration and the error signal,e, respectively. In some cases, the smoothing inverse filters 1183 mayalso receive the control output, u_(out_k−1), from the previousiteration, where the previous iteration's control output is receivedfrom the selector module 1108. The smoothing inverse filter 1183provides an inverse filtered version of the error signal, H⁻¹{e}, and aninverse filtered version of the previous iteration's control output,H⁻¹{u_(out_k−1)}, to the tensor multiply module 1112.

In some examples, the AIL control law module 1114 is configured to forma Matrix Tensor (e.g., a Sylvester matrix tensor) from the first set ofestimated model parameter tensors, [Θ], received from the FELB 1104.This Sylvester matrix tensor is then passed through a tensorpseudo-inverse block, which carries the pseudo-inverse operation onevery Sylvester matrix in all tensor dimensions. The Sylvester matricesare used to condense the estimated model parameters (Θ's) of the Â,{circumflex over (B)} matrices into a 2n×2n matrix for each input andeach time sample, leading to a tensor for these matrices. In some othercases, the Sylvester matrices are used to condense the estimated modelparameters (Θ's) the estimated coefficients (e.g., a_(est) and b_(est),described later in the disclosure) of the nonlinear model into a 2n×2nmatrix for each input and each time sample.

In some cases, the tensor multiply module 1112 applies a tensormultiplication between A_(CL) and the pseudo-inverse of the Sylvestermatrices tensor to obtain the tensor of matrices {circumflex over (P)}and {circumflex over (L)}. {circumflex over (P)} and {circumflex over(L)} may represent a linear algebraic transformation (also known asdiffeomorphism) and may be used to compute the adaptive control law. Inone non-limiting example, the tensor multiply module 1112 passes thetensor of Sylvester matrices and A_(CL) to the transformation module1188, which then computes the tensor of matrices, {circumflex over (P)}and {circumflex over (L)}, and passes them back to the tensor multiplymodule 1112.

{{circumflex over (P)},{circumflex over (L)}}=T{pinv(S)A_(CL)}  (Equation 10)

In equation (10), ‘S’ is a tensor of Sylvester matrices and ‘T’represents a linear algebraic transformation.

After receiving {{circumflex over (P)},{circumflex over (L)}} from thetransformation module 1188, the tensor multiply module 1112 carries outa tensor (or matrix) multiplication between {circumflex over (P)} andthe inverse filtered error signal, H⁻¹{e}. Further, the tensor Q_(m),which is the internal model representing the desired/reference plasmaprocess, is tensor multiplied with L. In some cases, the tensor Q_(m) isthe filtered variation of the tensor W_(m), where W_(m) is atime-varying linear system used in the nonlinear model, and typically inthe estimation portion of the nonlinear model. In some cases, astructure of the time-varying linear system, W_(m), may bepre-calculated in a frame resynthesizer or accessed from anempirically-derived lookup table. Further, the same time-varying linearsystem, W_(m), may be used for all iterations of a given frame, and thenchanged for a next frame. In some examples, the possible control signal,u_(SE_AIL), produced by the AIL control law module 1114 may becalculated as shown in equation (11) below:

u _(SE_AIL) =[H{u _(out_k−1) }−{circumflex over (L)}Q _(m) ]H ⁻¹ {u_(out_k−1) }−{circumflex over (P)}H ⁻¹ {e}  (Equation 11)

In some cases, the adaptive engine 1100 also computes one or more of thepossible control signals, u_(SE_PL) and u_(SE_EL), corresponding to thepenalty laws module 1134 and the eigen laws module 1124, respectively.For example, the TARC adaptive engine utilizes the adaptive tensor ofmatrices laws (ATML) module 1206 to compute an estimated output error,ê_(out), which is then used to compute the possible control signals forthe Eigen and Penalty control laws modules.

FIG. 13A illustrates a pre-computation block 1300-a of the ATML module1166, in accordance with one or more implementations. In some cases, theATML module 1166 may be similar or substantially similar to the ATMLmodule 1166 previous described in relation to FIG. 11A. As seen, thepre-computation block 1300-a comprises one or more tensor multiplymodules 1312, a sample delay (e.g., 1 sample delay, shown as 1-sd), andone or more summers.

As noted above, the adaptation and estimation laws module (shown as FELB1104 in FIG. 11A) produces a plurality of sets of estimated parametertensors, Θ, based on applying the one or more estimation laws to aninput regressor, where the input regressor includes one or more of (1)the estimation error, ê_(actual), (2) the control output from theprevious iteration, u_(out_k−1), (3) Q_(m), (4) time-varying linearsystem, W_(m), (5) reference signal or setpoint stream, r, (6) measuredoutput, y_(meas), and (7) estimated parameter tensors Θ for the previousiteration.

In some cases, the system estimation model may be represented using alinear time varying (LTV) representation (or the time-varying linearsystem, W_(m)). The LTV representation of the system estimation modelmay be updated every time sample, which enables modeling thenon-linearities, chaotic and dynamic nature, etc., of the non-linearsystem being controlled to a high degree of precision. In some cases,Equations (12) and (13) represent the LTV representation of the systemestimation model:

{dot over (x)}=Â(t){circumflex over (x)}(t)+{circumflex over (B)}(t)u_(out)(t),  (Equation 12)

ŷ(t)=C{circumflex over (x)}(t),  (Equation 13)

The Initial Condition (IC) in equations (12) and (13) is given as{circumflex over (x)}(0)=x₀.

Further, the matrices Â(t), {circumflex over (B)}(t), and C(t) may berepresented (in observer form) as follows:

$\begin{matrix}{{\hat{A}(t)} = \begin{bmatrix} & \begin{bmatrix}1 & \ldots & 0 \\ \vdots & \ddots & \vdots \\0 & \ldots & 1\end{bmatrix} \\ & 0\end{bmatrix}} & \left( {{Equation}14} \right)\end{matrix}$ $\begin{matrix}{{\hat{B}(t)} = \left\lbrack {(t)(t)(t)\ldots(t)(t)} \right\rbrack} & \left( {{Equation}15} \right)\end{matrix}$ $\begin{matrix}{{C(t)} = {I_{n \times n}\begin{bmatrix}1 & \ldots & 0 \\ \vdots & \ddots & \vdots \\0 & \ldots & 1\end{bmatrix}}} & \left( {{Equation}16} \right)\end{matrix}$

In Equations 14-16 above, ‘n’ is the order of the system representation(e.g., 1^(st) order, 2^(nd) order, 4^(th) order, etc.). Further, ‘m’ isthe number of control inputs/actuators in the non-linear system beingcontrolled. Some non-limiting examples of the control inputs/actuatorsbeing controlled include drive, rail, frequency, matching network firstconfiguration/position, matching network second configuration/position,etc. In some cases, ‘I’ is a n×n identity matrix (or alternatively, anidentity tensor). Thus, Â(t) is a matrix or tensor of dimension “n×n”,$(t) is a matrix or tensor of dimension “n×m”, and C(t) is an identitymatrix/tensor of dimension “n×n”.

The pre-processing block (i.e., pre-computation block 1300-a) of theATML module 1166 is configured to map the set of estimated parametertensors, Θ, received from the FELB 1104 for each of the eigen andpenalty control laws modules to the matrices Â(t) and {circumflex over(B)}(t) as follows:

θ=[θ_(a),θ_(b)]−θ(t)=[θ_(a)(θ_(b) ₁ (t),θ_(b) ₂ (t), . . . θ_(b) _(m)(t)]  (Equation 17)

The pre-computation block 1300-a then computes the estimated outputerror, ê_(out), for the ATML block as follows:

ê _(out) _(k) =(Â(t)ê _(out) _(k−1) )+(Â−A _(CL) _(E) )[Cê _(out) _(k−1)−(y _(meas) −r)]  (Equation 18)

Specifically, the tensor multiply module 1312 tensor multiplies Â(t) andC(t) with the actual estimation error for the previous iteration,ê_(out) _(k−1) , to produce (1) Â(t)ê_(out) _(k−1) , and (2) C(t)ê_(out)_(k−1) . Further, the measurement error, ê, which corresponds to adifference between the measured output, y_(meas), and the referencesignal, r, is calculated. This measurement error, e, given by|y_(meas)−r| is subtracted from C(t) ê_(actual) _(k−1) to produce:

C(t)ê _(actual) _(k−1) −(y _(meas) −r)  (Equation 19)

Next, the pre-computation block 1300-a computes ê_(out) (shown inequation 18) based on computing the difference between equations (20)and (21) shown below:

Â(t)ê _(out) _(k−1)   (Equation 20)

(Â−A _(CL) _(E) )[Cê _(out) _(k−1) −(y _(meas) −r)]  (Equation 21)

In the equations 18-21 above, A_(CLE) represents the observer formtensor of a matrix representation of the Eigenvalues, where theEigenvalues correspond to the speed of the estimation lawmodule/estimator (i.e., how fast the estimator is designed to be). Insome aspects, this design is similar to the filtering time-constants ofthe smoothing filters H{·}. In some examples, the pre-computation block1300-a is configured to compute the estimated output error for thetensor of the plurality of estimation law outputs (e.g., if all theestimation laws are being used).

FIG. 13B illustrates a block diagram 1300-b of the Eigen control lawsmodule 1124, in accordance with one or more implementations. The Eigencontrol laws module 1124 (also referred to as the EL module 1124)comprises an eigen solver 1326, a tensor multiply module 1112, smoothingfilters 1182, a sample delay (e.g., 1-sample delay), one or moresummers, and a discrete time integrator 1347 (DTI). As seen, the eigensolver 1326 of the EL module 1124 is configured to receive the Â(t) and{circumflex over (B)}(t) matrices, where the Â(t) and {circumflex over(B)}(t) matrices are computed based on the estimated model parametertensors, Θ, for a non-linear model of the one or more actuators and/orthe power system controlled by the one or more actuators. The eigensolver 1326 may also receive A_(CL), where A_(CL) Corresponds to amatrix (or tensor) of a time-varying linear system (LTV) representationof the non-linear waveform desired by the user as the output of thenon-linear system (e.g., a plasma system, a plasma processing chamber, apower system, to name a few non-limiting examples). The eigen solver1326 solves the following matching problem: Eigenvalues (Â−{circumflexover (B)}Ω)=Eigenvalues (A_(CL)). This results in an output tensor, Ω,that is passed to the tensor multiply module 1112. The tensor multiplymodule 1112 of the EL module 1124 receives the Ω tensor, which is thentensor multiplied with the tensor Q_(m), where Q_(m) is the same orsubstantially the same as the Q_(m) described in relation to FIG. 11 .For example, Q_(m) may represent an internal model representing thedesired/reference plasma process performance. The tensor multiply module1112 passes Q_(m), to the smoothing filters 1182, where it issmoothed/filtered to produce the possible control signal (u_(SE_EL)) forthe EL module 1124. In other words, the possible control signal,u_(SE_EL), may be represented as H{Ω_(m)Ω}. This possible controlsignal, u_(SE_EL), is passed to the CSC 1107, along with the possiblecontrol signals, u_(SE_AIL) and u_(SE_PL), for the AIL and penaltycontrol laws modules.

In some embodiments, the Eigen control law module 1124 (oralternatively, the FELB 1104) computes an estimated system output,y_(est_SE_EL) (e.g., via an estimation portion of the nonlinear modeland in particular via the time-varying linear system, W_(m)), for theEigen control law module 1124 and passes it to one or more of the CSC1107 and the selector module 1108. In some examples, the estimatedsystem output, y_(est_SE_EL)(k), may be generated by feeding thepossible control signal for the current iteration, u_(SE_EL)(k), intothe estimation portion of the nonlinear model, possibly including thetime-varying linear system, W_(m), as described above in relation toFIG. 8B. This estimated system output, y_(est_SE_EL)(k), may also bereferred to as possible estimated system output, since it is based on apossible control signal produced by a control law module. In othercases, the estimated system output, y_(est_SE_EL)(k−1) may be generatedby applying the estimation portion to the possible control signal,u_(SE_EL)(k−1), for the previous iteration, as discussed in relation toFIG. 8A.

As seen, in some cases, the FELB 1104 (or the parametric/non-linearmodel) may receive the previous iteration's control output, u_(out_k−1),from the selector module 1108. In such cases, if thenon-linear/estimation portion/W_(m) is in the FELB 1104, a totalestimated system output, y_(est_out)(k), is computed based on applyingthe control output, u_(out_k−1), from the previous iteration to theestimation portion of the model. The topology selector and designer(TSD) of the selector module uses this estimated system output (alsoreferred to as an estimated system output for adaptation) for selectingthe different weights applied to the different possible control signalsto produce the final/actual control output signal, u_(out), sent fromthe selector module 1108 to the one or more actuators. In some examples,the adaptive engine 1100 updates the possible estimated system output,y_(est_SE)(k−1), for the previous iteration when the control output,u_(out), from the previous iteration is different than the possiblecontrol signal, u_(SE)(k−1), for the previous iteration. In such cases,the possible estimated system output, y_(est_SE)(k−1), is updated byapplying the estimation portion of the nonlinear model to the actualcontrol output, u_(out), from the previous iteration (k−1). The adaptiveengine 1100 may u_(se) this updated y_(est_SE)(k−1) to compute thepossible estimated system output, y_(est_SE)(k), for the currentiteration. For example, the adaptive engine 1100 may computey_(est_SE)(k) as: y_(est_SE)(k)=updated version of y_(est_SE)(k−1)+{dotover (y)}_(SE) _(est) (k), which corresponds to a corrected integrationin the discrete time domain.

In some examples, the selector module 1108 passes a total estimatedsystem output, y_(est_out)(k), to the estimation law module/FELB 1104.When this total estimated system output, y_(est_out)(k), is receivedfrom the selector module 1108, it may be formed as a selection of thebest possible estimated system output, y_(est_se), received from thedifferent estimation-control law module pairs (i.e., FELB-control lawsub-engine pairs), or a combination of the different possible estimatedsystem outputs, y_(est_se), received from the various estimation-controllaw module pairs. In some embodiments, the selector module 1108 utilizesthe same or similar topology and underlying math used to compute thefinal/actual control output signal, u_(out). Said another way, thisestimated system output for adaptation, y_(est_out)(k), may be produced(e.g., by the CSC of the selector module) by combining possibleestimated system outputs, y_(est_se), from different estimation-controllaw module pairs, which may be similar to the way that the total controloutput, u_(out), is computed from one of (or a combination of) differentpossible control signals, u_(se). For instance, see Equation 7.

In some embodiments, the eigen control laws module 1124 is alsoconfigured to produce the estimation error, ê, and/or a possible controlsignal, u_(se_EL), for the next iteration (or time instant). Forexample, the tensor multiply module 1112 tensor multiplies {circumflexover (B)} with the tensor, Ω, to produce {circumflex over (B)}Ω, whichis then subtracted from the estimated output error (ê_(out)), asfollows:

{circumflex over (ē)}=ê _(out) −{circumflex over (B)}Ω  (Equation 22)

The estimation error, ê, may be calculated by passing {circumflex over(ē)} through DTI 1347. This estimation error, ê, is passed through a1-sample delay (shown as 1-sd in FIG. 13A) and fed back to the tensormultiply module 1112.

FIG. 13C illustrates a block diagram 1300-c showing the penalty controllaws module 1134, in accordance with one or more implementations. Thepenalty control laws module 1134 (also referred to as the PL module1134) comprises a tensor multiply module 1112, smoothing filters 1182,equation solvers 1383, DTI 1347, 1-sample delay, and at least onesummer. Similar to the eigen control laws module described in relationto FIG. 13A, the penalty control laws module 1134 uses an equationsolver to solve for a tensor, P. Specifically, the equation solver(s) ofthe PL module 1134 receives a penalty tensor R (or alternatively, apseudo-inverse (pinv) of the penalty tensor, R), and the Â(t),{circumflex over (B)}(t), and C(t) matrices described above, anddetermines the tensor, P, where the tensor, P, corresponds to a solutionof a continuous time equation. In one non-limiting example, the tensor,P, is a solution of the equation:

Â ^(T) P+PÂ−pinν(R)P{circumflex over (B)}{circumflex over (B)} ^(T) P+CC^(T)=0  (Equation 23)

In some other cases, the tensor, P, may be determined from thediscrete-time counterpart of the above equation. In either case, thetensor multiply module 1112 uses the tensor P, the pseudo-inverse of thepenalty tensor, pinν(R), and the estimation error, ê, to determine theinput to the smoothing filters 1182. The smoothing filters 1182 areconfigured to smooth/filter the signal received from the tensor multiplymodule 1112 and output the possible control signal, u_(SE_PL), for thePL module 1134 to the CSC 1107. In one non-limiting example, thesmoothing filters 1182 receives as input a signal defined by theequation:

−Q _(m) pinν(R){circumflex over (B)}Pê  (Equation 24)

In this case, the possible control ‘u_(SE_PL)’ output from the PL module1134 may be represented as follows:

u _(SE_PL) =H{−Q _(m)pinv(R){circumflex over (B)}Pê}  (Equation 25)

In some examples, the tensor multiply module 1112 also passes a signal(e.g., given by pinv(R){circumflex over (B)}Pê) to a summer, where it issubtracted from the estimated output error, ê_(out), to determine{circumflex over (ē)}. In other words, {circumflex over (ē)} may berepresented as follows:

{circumflex over (ē)}=ê _(out)−pinv(R){circumflex over (B)}Pê  (Equation26)

As shown, the output, {circumflex over (ē)}, of the summer is passedthrough the discrete time integrator (DTI) 1347 to obtain the estimationerror, ê. In some embodiments, the estimation error, ê, is fed back tothe tensor multiply module 1112 after passing it through the 1-sampledelay (shown as sample delay in FIG. 13B).

FIG. 12 illustrates an example of a method 1200 for controlling anon-linear system using the TARC sub engine described above in relationto FIGS. 11A-11C and 13A-13C, in accordance with one or moreimplementations. The operations of method 1200 presented below areintended to be illustrative. In some implementations, method 1200 may beaccomplished with one or more additional operations not described,and/or without one or more of the operations discussed. Additionally,the order in which the operations of method 1200 are illustrated in FIG.12 and described below is not intended to be limiting.

In some implementations, method 1200 may be implemented in one or moreprocessing devices (e.g., a central processing unit or CPU, a digitalprocessor, an analog processor, a digital circuit designed to processinformation, an analog circuit designed to process information, a statemachine, a field programmable gate array or FPGA, and/or othermechanisms for electronically processing information). The one or moreprocessing devices may include one or more devices executing some or allof the operations of method 1200 in response to instructions storedelectronically on an electronic storage medium. The one or moreprocessing devices may include one or more devices configured throughhardware, firmware, and/or software to be specifically designed forexecution of one or more of the operations of method 1200.

A first operation 1202 comprises receiving an input regressor and areference signal, r. In some examples, the input regressor and thereference signal, r, may be received at the estimation law module (alsoreferred to as the estimation law module or the FELB, in some examples)of the adaptive engine. In one non-limiting example, the input regressorand the reference signal are received at the estimation law module/FELB1104. The input regressor may comprise a system output measurement,y_(meas), and a control output, u_(out_k−1), from a previous iteration.The input regressor may include additional components besides the oneslisted above and the examples listed herein are not intended to belimiting. In some examples, the first operation 1202 may be performed byone or more hardware processors configured by machine-readableinstructions including a module that is the same as or similar to theestimation law module 1104, in accordance with one or moreimplementations.

A second operation 1204 comprises applying one or more estimation lawsto the input regressor to estimate two or more sets of estimated modelparameter tensors, Θ, for a nonlinear model. In some examples, thenonlinear model is a function of the two or more sets of estimated modelparameter tensors, Θ. Further, each of the two or more sets of estimatedmodel parameter tensors, Θ, comprises estimated parameters of thenonlinear model. In some examples, the second operation 1204 may beperformed by one or more hardware processors configured bymachine-readable instructions including a module that is the same as orsimilar to the estimation law module 1104, in accordance with one ormore implementations.

A third operation 1206 comprises receiving a possible control signal,u_(SE), from each of first and second control law modules of a controllaw sub-engine (e.g., TARC control law module/sub-engine 1106). Morespecifically, third operation 1206 comprises receiving two or morepossible control signals, u_(SE_k), each using a corresponding controlportion of the nonlinear model, where each control portion is a functionof one of the two or more sets of estimated parameter tensors, Θ, of thenonlinear model. Some non-limiting examples of the control modules(e.g., first, second control law modules) may include the AdaptiveInverse Laws (AIL) control law module, the penalty control law module,and the Eigen control law module. Further, the two or more possiblecontrol signals, u_(SE_k), may be received by one or more of theestimation law module 1104, the control selector and combiner (CSC)1107, the CSC 1116, and the selector module 1108. A control portion ofthe nonlinear model may be implemented in the control law sub-engine totake the two or more sets of estimated parameter tensors, Θ, and producethe possible control signals, u_(SE_k).

A fourth operation 1208 comprises producing (or generating) two or morepossible estimated system outputs, y_(est_SE), based upon applying thenonlinear model to (1) a previous iteration of the possible controlsignal, u_(SE_k−1), from one of the two or more control portions, or (2)the possible control signal, u_(SE_k), from one of the two or morecontrol portions. Additionally, or alternatively, fourth operation 1208comprises generating two or more estimated system outputs, y_(est_SE),each using a corresponding estimation portion of the nonlinear model,where each estimation portion is a function of one of the two or moresets of estimated model parameter tensors, Θ. In some examples, eachestimation portion is also a function of a structure of the time varyinglinear system, W_(m). Further, each of the one or more estimation lawsmay be a function of an estimation error, ê, or a cost function, J. Insome examples, the fourth operation 1208 may be performed by one or morehardware processors configured by machine-readable instructionsincluding a module that is the same as or similar to the estimation lawmodule 1104, or a module that is the same as or similar to the controllaw module/sub-engine 1106, in accordance with one or moreimplementations.

A fifth operation 1210 comprises provide one of, or a combination of,the two or more possible control signals, u_(SE), to a selector module(e.g., selector module 1108) based at least in part on anestimation/prediction error derived from each of the possible estimatedsystem outputs, y_(est_SE). In some examples, fifth operation 1210comprises selecting (1) a best possible control signal, u_(SE), from aset comprising at least the first possible control signal and the secondpossible control signal, or (2) a best combination of possible controlsignals, u_(SE), blended from two or more of the set. For example, theCSC 1107 may select one of, or a combination of the possible controlsignals, u_(SE_k), output from each of the Eigen, Penalty, and AdaptiveInverse Law control law modules 1124, 1134, and 1114, respectively,predicted to minimize error. In some examples, the fifth operation 1210may be performed by one or more hardware processors configured bymachine-readable instructions including a module that is the same as orsimilar to the CSC 1107 (or CSC 1108), in accordance with one or moreimplementations.

Although not illustrated, the TARC sub-engine can operate as astandalone controller. In such an embodiment, the estimation lawmodules/FELB can be replaced by an empirically derived lookup table forthe estimated model parameter tensors, Θ. More specifically, a lookuptable can be empirically formed as a mapping between (1) y_(meas) andu_(out) from a reference/calibration system and (2) estimated modelparameter tensors, Θ. During operation of the TARC as a standalonecontroller, a control, u_(out), can be provided to the one or moreactuators, and measurements, y_(meas), can be taken from the one or moreactuators and/or system. These can then be used to select estimatedmodel parameter tensors, Θ, from the lookup table, and then provided tothe TARC standalone controller to determine what will be called acontrol signal, u_(out). This control signal, u_(out), can be providedto the one or more actuators. Alternatively, the TARC standalonecontroller can produce a string of possible control signals, u_(se), andform a control, u_(out), as a combination of the string. For instance, aweighted average of the possible control signals, u_(se), can be used tocalculate the control, u_(out), although other methods of combining thestring can also be implemented. In some embodiments, the combination maybe based on estimated system outputs, y_(est_se), for each of thepossible control signals, u_(se), similar to the way in which a topologyis selected in the selector and combiner mentioned earlier. Theseestimated system outputs, y_(est_se), can be found via an estimationportion of the nonlinear model, for instance, using Model 1:

y _(est_se) =W _(m) {u _(se),Θ}

Where the estimated model parameter tensor, Θ, is found in the lookuptable based on the measured system output, y_(meas), and the control,u_(out), both from a previous iteration.

The Tensorized Filtered Predictive-Adaptive (TFPA) Sub Engine

As noted above, in some circumstances, the TLMC (Lyapunov) control lawmodule's output (e.g., estimated system output, y_(est_SE); measuredsystem output, y_(meas)) may not converge to a steady-state behavior,for instance, due to having predicted unstable zero dynamics. In suchcases, the TLMC control law module's output may comprise disturbances,dither, and/or noise. In some examples, extra filtering may helpmitigate the effects of some of these issues. In most cases, this extrafiltering is simply a “band-aid solution/fix”, meaning it does notaddress the underlying cause of the predicted unstable zero dynamics. Inother cases, however, the system being controlled may go unstable. Toalleviate the risk of the entire non-linear system going unstable,aspects of the present disclosure are directed to a control lawsub-engine (herein referred to as the TFPA sub-engine) that isspecifically designed to handle unstable zero dynamics predictions. Insome examples, the TFPA sub-engine is configured to produce a possiblecontrol signal, u_(SE), that can be provided as another possible controlsignal input to the selector module. In other words, the selector moduleof the adaptive engine is configured to receive the possible controlsignal, u_(SE), from the TFPA sub-engine, in addition to or in lieu ofthe possible control signal(s) received from the TLMC sub-engine, theTARC sub-engine, and/or any of the other sub-engines described herein.In some instances, the selector module may utilize the possible controlsignal provided by the TFPA sub-engine in the case of stable zerodynamics situations, unstable zero dynamics predictions, or acombination thereof. In yet other cases, the TFPA sub-engine can operateas a standalone controller and receive estimated model parametertensors, Θ, from an empirically derived lookup table.

Turning now to FIG. 14 , which depicts a block diagram of an adaptiveengine 1400-a with details of the control law module (or control lawsub-engine) shown. As seen, the adaptive engine 1400-a includes at leastone estimation law module 1404 (also referred to as FELB 1404), acontrol law module or sub engine 1405, and a selector module 1488. Aswith other adaptive engines discussed herein, the FELB 1404 isconfigured to receive one or more of an input regressor, Ø, a structureof the non-linear model, W_(m), of the one or more actuators and/or thepower system controlled by the one or more actuators, a referencesignal, r, a system output measurement, y_(meas), an estimated systemoutput, y_(est), a control output, u_(out_k−1), from a previousiteration, and a possible control signal, u_(SE), produced by thecontrol law module or sub engine 1405. In some embodiments, theestimation law module or FELB 1404 estimates a model parameter tensor,Θ, for the non-linear model. Further, the control law module/sub-engine1405 utilizes the estimated model parameter tensor, Θ, received from theFELB 1404 to produce a possible control signal, u_(SE), and optionally,an estimated system output, y_(est_SE) (e.g., via an estimation portionof the nonlinear model and in particular via a time-varying linearsystem, W_(m), whose structure is updated every frame). In other cases,the control law module 1405 provides the possible control signal,u_(SE), to the FELB 1404, where it is utilized to produce the estimatedsystem output.

In the example shown, the control law module 1405 comprises one or morefilters 1410, one or more delay filter 1411, a sliding mode predictor1409 comprising a non-linear (NL) model 1408 of the system and/oractuators, a NL compensation module 1413, and an optional tensorsynchronization and coherency module 1427 (also referred to as tensorsync module 1427, for the sake of brevity). In some examples, thecontrol law module 1406 of the control law sub engine 1405 is configuredto receive the estimated model parameter tensors, Θ, from the FELB 1404,along with one or more of the control output from the previousiteration, u_(out_k−1), measured system output, y_(meas), and thefiltered measured system output, y_(d). The control law module 1406 usesthe estimated model parameter tensors, Θ, and one or more of the inputs(e.g., y_(d), y_(meas), u_(out_k−1)) to produce a desired (butunfiltered) possible control signal, which is input to the delay filters1411. The delay filters 1411 adjust for delays and outputs a desired andfiltered possible control signal, u_(desired). The NL compensationmodule 1413, which may be implemented using one or more NL transferfunctions, is configured to compensate for non-linearities (if any) inthe control signal, u_(desired), and produce the possible controlsignal, u_(SE), that is finally sent to the selector module 1488. Insome cases, the sliding mode predictor 1409 is configured to produce anestimated system output, y_(est_SE), where the estimated system outputis based at least in part on the possible control signal and theestimated parameter tensors, Θ. For example, the sliding mode predictor1409 applies the possible control signal to the NL model 1408 of thesystem, where the NL model 1408 comprises the estimated model parametertensor, Θ, to produce the estimated system output, y_(est_SE) (e.g., viaan estimation portion of the nonlinear model and in particular via atime-varying linear system, W_(m), whose structure is updated everyframe). In some examples, the sliding mode predictor 1409 also receivesthe control output, u_(out), from the previous iteration, where thecontrol output is received from one of the selector module 1488 or thetensor sync module 1427. In this example, the selector module 1488passes the control output, u_(out), to the tensor sync module 1427,where it is processed before forwarding to the NL model 1408. In somecases, processing the control output comprises applying an exogenoussignal (e.g., received from the FELB 1404, the selector module 1488, orany other applicable entity) to the control output, which helps smoothtransitions between possible control signals (e.g., u_(SE), u_(SE1),u_(SE2), u_(SEn), etc.) input to the selector module 1488. In this case,however, the exogenous signal is applied to the control output, u_(out),from the previous iteration. In such cases, the tensor sync module 1427uses the exogenous signal to perform an operation (e.g., adding anoffset) to reduce/minimize discontinuities due to a mismatch (if any)between the previously used control law and the current control law.Broadly, the tensor sync module 1427 helps ensure smooth, coherent,and/or synchronized transitions when the adaptive engine is switchingbetween different control law sub-engines (e.g., TARC sub-engine, TLMCsub-engine, and any of the other sub-engines described herein) and/orcontrol law modules within the same sub-engine (e.g., adaptive inverselaws module, penalty laws module, and Eigen laws module of the TARCsub-engine).

In some embodiments, the NL model 1408 is configured to produce apossible estimated system output, y_(est_SE), for the control law subengine 1405, based upon applying the possible control signal, u_(SE), tothe non-linear model. The NL model 1408 may also produce a totalestimated system output, y_(est_out), based upon applying the iterationof the control output, u_(out), to the non-linear model. In somecircumstances, the nonlinear model or NL model 1408 may also pass anestimated system output, y_(est_ideal), to the NL compensation module1413 where it is transformed to produce the possible estimated systemoutput, y_(est_SE). In some cases, y_(est_ideal), may be produced usingthe possible control signal, u_(SE). In some embodiments, the totalestimated system output, y_(est_out), is sent to a summer, where it issubtracted from the filtered system output measurement, y_(d), todetermine an estimation error (ê). The estimation error, ê, is passed tothe estimation law module/FELB 1404, where it is used (i.e., in additionto the input regressor, Ø) to generate the estimated model parametertensor, Θ.

In some examples, the control law module 1406 of the control lawsub-engine also receives the control output, where the control output isreceived from one of the tensor sync module 1427 (e.g., after passing itthrough the 1-sample delay) or the selector module 1488. In some cases,this control output is the control output from the previous iteration(e.g., u_(out_k−1)).

In some examples, the sliding mode predictor 1409 is configured to read(1) an initial linear time varying (LTV) signal (e.g., W_(m)) receivedfrom a setpoint streaming module (not shown), where the setpointstreaming module provides the setpoint stream (also referred to as aseries of setpoints, or a reference signal, r), and (2) an internallygenerated LTV signal derived from the desired arbitrary waveformspecified by the user. In some embodiments, the initial LTV signalcorresponding to the setpoint stream is used as an initial model foradaptation at a start of each frame, each frame comprising a pluralityof samples. As described above, W_(m)(t) at time instant ‘k’ is a linearmodel and indirectly specified by the user/designer. The framesynthesizer (not shown) helps approximate the non-linear behavior ofW_(m). In some cases, the structure of W_(m)(t) is provided once forevery frame, but the W_(m)(t) is updated every iteration or controlsample and then used to form the closest linear model of the setpointstream. In some embodiments, the sliding mode predictor 1409 of thecontrol law sub-engine 1405 is further configured to receive one or moreLTV signals adapted from the initial LTV signal, where each of the oneor more LTV signals are adapted from the initial LTV signal andcorrespond to one sample of the plurality of samples of a correspondingframe. In this way, the sliding mode predictor 1409 uses the LTVsignal(s) to predict how the system/plant may react in a non-linearfashion. Furthermore, due to its sliding mode nature, the predictionoutput rapidly and robustly converges, which is especially importantwhile dealing with highly non-linear and chaotic systems. As such, thedisclosed TFPA sub-engine optimizes control of non-linear systems, suchas those having unstable zero dynamics.

In some cases, the sliding mode predictor 1409 (or the control lawmodule 1406) generates the control law (e.g., similar or substantiallysimilar to Control Law 3 described in the preceding sections) asfollows:

u _(pred)=θ_(u) _(d) u _(out)+θ_(y) _(d) y _(d)+θ_(y) _(pred) y_(pred)+θ_(r) r  (Equation 27)

In equation (27), the estimated model parameter tensor, Θ, can bewritten as:

θ=[θ_(u) _(d) ,θ_(y) _(d) ,θ_(y) _(meas) ,θ_(r)]  (Equation 28)

Further, the sliding mode predictor's equations (e.g., in the continuoustime domain) may be given as:

$\begin{matrix}{{\overset{.}{\hat{x}}}_{est} = {{{A(t)}x_{est}} + {{B(t)}u_{pred}} - {K\left( {y_{est} - y_{meas}} \right)} + {{{pinv}(L)}{CFv}}}} & \left( {{Equation}29} \right)\end{matrix}$ $\begin{matrix}{{where},{v = \left\{ \begin{matrix}\left\{ {{- {\alpha\left( {t,y_{meas},u_{out}} \right)}}{FCpinv}{{FC}}} \right. & \left| {{FC} \neq 0} \right. \\0 & \left| {else} \right.\end{matrix} \right.}} & \left( {{Equation}30} \right)\end{matrix}$

In equations (29) and (30) above, ν is an exogenous signal.Additionally, the A(t) and B(t) matrices are generated in the adaptiveengine 1400-a based on the desired arbitrary waveform (e.g., referencesignal, r) specified by the user and received from a setpoint streamingmodule. In some aspects, the A(t) and B(t) matrices represent thedynamics of W_(m). Further, K is the gain tensor. In some cases, thegain tensor, K, may be updated whenever the A(t), B(t) and/or C(t)matrices are updated. Further, the output matrix/tensor, C(t), may beused to calculate the estimated system output (e.g., y_(est_SE),y_(est_out)) as shown in equation (31) below:

y _(est) =C(t)x _(est)  (Equation 31)

In some cases, the matrix C(t) may be similar or substantially similarto the one described above in relation to the TARC Sub Engine. Forinstance, C(t) may be an n-by-n identity matrix, in some examples.Furthermore, L in equation (29) may be a tensor of matrices that can beused to solve a Lyapunov equation for every A(t), C(t), K(t), and anoptional strictly positive real (SPR) matrix or tensor, Q(t). In onenon-limiting example, Q(t) may also be an identity matrix (or identitytensor). In other cases, Q(t), which corresponds to a penalty or gaintensor may not be an identity tensor and may be specified by theuser/designer. Specifically, the tensor, L, may be used to solve aLyapunov equation of the form:

[A(t)−K(t)C(t)]L+L[A(t)−K(t)C(t)]T+Q=0  (Equation 32)

Using equation (32), F(t) (in the sliding mode predictor's equations 29and 30) can be computed as follows:

F(t)=C(t)L(t)B(t)pinν(CC ^(T))  (Equation 33)

As noted above, the exogenous signal, ν, can be written using Equation(30). In equation (30), a, is a tuning coefficient and is a function oftime, t, the system output measurement, y_(meas), and the controloutput, u_(out). In some cases, the tuning coefficient, a, follows anoptimization law, where the optimization law may be designed offline(e.g., using Pontryagin's minimum principle) or computed online (e.g.,when the non-linear system is live/deployed/active). In some othercases, the tuning coefficient, a, is a positive constant.

In some embodiments, one or more of the setpoint streaming module, aprecomputing engine (e.g., used to determine the A(t), B(t), C(t), K(t),L(t), F(t) matrices/tensors), and a frame synthesizer may be implementedon a Central Processing Unit (CPU). This allows the CPU, rather than theField Programmable Gate Array (FPGA), to handle the heavy/intensivecomputations in an offline (or pseudo-offline) manner. On the otherhand, the FPGA is better suited for performing simpler calculations in avery rapid manner (e.g., real-time or substantially real-time). Theprecomputing engine on the CPU sends the A(t), B(t), C(t), K(t), L(t),and/or F(t) matrices/tensors to the adaptive engine running on the FPGA.In some cases, the CPU also stores these matrices/tensors at a frameprocessor of the FPGA, for instance, in a TSP RAM of the frameprocessor. This allows the adaptive engine and/or the control lawmodule/sub-engine to access the precomputed matrices in real time orsubstantially real time.

In some cases, a setpoint streaming engine/module of the CPU receivesthe reference signal, r, which may be an arbitrary waveform desired bythe user, and creates a plurality of internal values that are based onthe reference signal. The precomputing engine receives these internallygenerated values from the setpoint streaming engine/module and maps themto the matrices/tensors A(t), B(t), C(t), etc. Thus, some non-limitingexamples of the precomputed matrices/tensors (also referred to as framemapped tensors) include: {A(t), B(t), C(t), K(t), L(t), pinv(L(t)),F(t), pinv(L(t)C(t)), F(t), ν}

In an alternate representation (i.e., alternate to equation 28), theestimated model parameter tensor, Θ, may be given as follows:

θ=[θ_(u) _(out) ,θ_(y) _(d) ,θ_(y) _(est) ,θ_(r)]  (Equation 34)

From equation (34), it can be seen that the estimated model parametertensor, θ, is a function of the estimation error, ê, since theestimation error, ê, is determined from a difference between theestimated/predicted system output, y_(est), and the measured systemoutput (after filtering), y_(d). In some embodiments, the estimatedparameter tensor, θ, computed by the estimation law module may be basedon the derivative of the estimated model parameter tensor, {dot over(θ)}, as described above and elsewhere in the disclosure.

The control law module/sub-engine 1405 then produces the possiblecontrol signal, u_(SE), where u_(SE) is a function of the estimatedmodel parameter tensor θ and the input regressor. Specifically, thepossible control signal, u_(SE), is generated by multiplying differentsub-components of the estimated model parameter tensor withcorresponding sub-components of the input regressor and then combiningthem (e.g., adding them) to produce the possible control signal, asfollows:

u _(se)=θ_(u) _(out) u _(out)+θ_(y) _(d) y+θ _(y) _(pred) y_(pred)+θ_(r) r  (Control Law 3)

In some examples, this control signal, u_(SE), is passed through thedelay filters 1411, which help reduce or minimize noise induced duringadaptation. In one non-limiting example, the delay filters 1411 compriseminimum lag/delay smoothing filters, but other types of delay filtersknown in the art are contemplated in different embodiments. In somecases, the smoothing/delay filter 1411 may be Gaussian in nature andimplemented as a combination of two bi-quads given by:

$\begin{matrix}{{H(z)} = {\frac{Y(z)}{X(z)} = \frac{b_{0}}{\left\lbrack {1 + {a_{1}z^{- 1}} + {a_{2}z^{- 2}} + {a_{3}z^{- 3}} + {a_{4}z^{- 4}}} \right.}}} & \left( {{Equation}35} \right)\end{matrix}$

In some examples, equation (35) may be a function of a delay, τ, whichmay be based on the desired response speed (e.g., rise time, T_(r))specified by the user. For example, τ may be written in generalized formas shown in equation (36) below:

$\begin{matrix}{\tau = \frac{\alpha}{\beta + \gamma}} & \left( {{Equation}36} \right)\end{matrix}$

In equation (36), α and β may be integers or decimal values, and γ maybe a function of T_(r), where T_(r) is the rise time (e.g., on the orderof 1 microsecond). In some cases, γ may optionally be a function of thecontrol rate, T_(control). In one non-limiting example, the controlrate, T_(control), may be on the order of around 250 n_(s)). While notnecessary, in most cases, T_(r)>T_(control).

The filter then passes the filtered possible control signal, u_(SE), tothe NL compensation module 1413, which is implemented by way of one ormore NL transfer functions. The NL compensation module 1413 compensatesfor any non-linearities in the control signal received from the filters1411 before passing the possible control signal, u_(SE), to the selectormodule 1488. The selector module 1488 also receives one or more otherpossible control signals from one or more other control lawmodules/sub-engines, sifts through their predictions/estimations, andselects the possible control signal (e.g., one of u_(SE), u_(SE1),u_(SE2), u_(SEn)) predicted to have the lowest estimation error as thecontrol output, u_(out). This control output, u_(out), is then appliedto the one or more actuators and/or the non-linear system controlled bythe one or more actuators to effectuate a change in the measured systemoutput so as to reduce the error between the reference signal, r, andthe measured system output, y_(meas).

FIG. 15 illustrates an example of a method 1500 for controlling anon-linear system using the TFPA sub engine, previously described inrelation to FIG. 14 , in accordance with one or more implementations.The operations of method 1500 presented below are intended to beillustrative. In some implementations, method 1500 may be accomplishedwith one or more additional operations not described, and/or without oneor more of the operations discussed. Additionally, the order in whichthe operations of method 1500 are illustrated in FIG. 15 and describedbelow is not intended to be limiting.

In some implementations, method 1500 may be implemented in one or moreprocessing devices (e.g., a central processing unit or CPU, a digitalprocessor, an analog processor, a digital circuit designed to processinformation, an analog circuit designed to process information, a statemachine, a field programmable gate array or FPGA, and/or othermechanisms for electronically processing information). The one or moreprocessing devices may include one or more devices executing some or allof the operations of method 1500 in response to instructions storedelectronically on an electronic storage medium. The one or moreprocessing devices may include one or more devices configured throughhardware, firmware, and/or software to be specifically designed forexecution of one or more of the operations of method 1500.

A first operation 1502 comprises receive an input regressor and areference signal, r. In some examples, the input regressor and thereference signal, r, may be received at the estimation law module (alsoreferred to as the estimation law module or the FELB, in some examples)of the adaptive engine. In one non-limiting example, the input regressorand the reference signal are received at the estimation law module/FELB1404. The input regressor may comprise a system output measurement,y_(meas), and a control output, u_(out_k−1), from a previous iteration.The input regressor may include additional components besides the oneslisted above and the examples listed herein are not intended to belimiting. In some examples, the first operation 1502 may be performed byone or more hardware processors configured by machine-readableinstructions including a module that is the same as or similar to theestimation law module 1404, in accordance with one or moreimplementations.

A second operation 1504 comprises apply one or more estimation laws tothe input regressor to produce one or more estimated parameter tensors,Θ, for a nonlinear (NL) model. In some examples, the nonlinear model isa function of the one or more estimated model parameter tensors, Θ.Further, each of the one or more estimated model parameter tensors, Θ,comprises estimated parameters of the nonlinear model. In some examples,the second operation 1504 may be performed by one or more hardwareprocessors configured by machine-readable instructions including amodule that is the same as or similar to the estimation law module 1404,in accordance with one or more implementations.

A third operation 1506 comprises receive a system output measurement,y_(meas), a control output from a previous iteration, u_(out_k−1), andthe one or more estimated parameter tensors Θ. In some examples, thethird operation 1506 may be performed by one or more hardware processorsconfigured by machine-readable instructions including a module that isthe same as or similar to the TFPA control law module/sub-engine 1405,in accordance with one or more implementations.

A fourth operation 1508 comprises receiving (1) an initial LTV signal(e.g., W_(m)) corresponding to the reference signal, r, and (2) apossible control signal, u_(SE), or an internal possible control signal,u_(SE_desired). In some examples, the fourth operation 1506 may beperformed by one or more hardware processors configured bymachine-readable instructions including a module that is the same as orsimilar to the sliding mode predictor 1409, in accordance with one ormore implementations. As seen in FIG. 14 , in some examples, the slidingmode predictor 1409 comprises the nonlinear model 1408.

In some examples, the possible control signal, u_(SE), or the internalpossible control signal, u_(desired), are generating using a controlportion of the nonlinear model, where the control portion is a functionof the one or more estimated parameter tensors, Θ, of the nonlinearmodel. In some cases, the control law module 1406 of the TFPA sub engine1405 generates the possible control signal, u_(SE), and/or the internalpossible control signal, u_(desired).

A fifth operation 1510 comprises producing (or generating) an internalpossible estimated system output, y_(est_ideal), and a possibleestimated system output, y_(est_SE). Generating the internal possibleestimated system output, y_(est_ideal), is based upon applying thenonlinear model (e.g., the estimation portion of the nonlinear model) tothe control output from the previous iteration, u_(out_k−1), and thesystem output measurement, y_(meas). Further, generating the possibleestimated system output, y_(est_SE), is based upon applying theestimation portion of the nonlinear model to (1) the internal possiblecontrol signal, u_(desired), (2) the possible control signal for thecurrent iteration, u_(SE_k), or (3) to the previous iteration of thepossible control signal, u_(SE_k−1). In some examples, each estimationportion is also a function of a structure of the time varying linearsystem, W_(m). Further, each of the one or more estimation laws may be afunction of an estimation error, ê, or a cost function, J.

In some examples, the fifth operation 1510 may be performed by one ormore hardware processors configured by machine-readable instructionsincluding a module that is the same as or similar to the sliding modepredictor 1409, or a module that is the same or similar to theestimation law module 1404 (e.g., if the estimation portion of thenonlinear model is in the estimation law module 1404) in accordance withone or more implementations. As seen in FIG. 14 , in some examples, thesliding mode predictor 1409 comprises the nonlinear model 1408.

A sixth operation 1512 comprises receiving the possible control signal,u_(SE), and the possible estimated system output, y_(est_SE). In someexamples, the sixth operation 1512 may be performed by one or morehardware processors configured by machine-readable instructionsincluding a module that is the same as or similar to the selector module1488, and/or the CSC 516, in accordance with one or moreimplementations. Optionally, the sixth operation 1512 may also beperformed by one or more hardware processors configured bymachine-readable instructions including a module that is the same as orsimilar to the estimation law module 1404.

Although not illustrated, the TFPA sub-engine can operate as astandalone controller. In such an embodiment, the estimation lawmodules/FELB can be replaced by an empirically derived lookup table forthe estimated model parameter tensors, Θ. More specifically, a lookuptable can be empirically formed as a mapping between (1) y_(meas) andu_(out) from a reference/calibration system and (2) estimated modelparameter tensors, Θ. During operation of the TFPA standalone controlleras a standalone controller, a control, u_(out), can be provided to theone or more actuators, and measurements, y_(meas), can be taken from theone or more actuators and/or system. These can then be used to selectestimated model parameter tensors, Θ, from the lookup table, and thenprovided to the TFPA standalone controller to determine what will becalled a control signal, u_(out). This control signal, u_(out), can beprovided to the one or more actuators. Alternatively, the TFPAstandalone controller can produce a string of possible control signals,u_(se), and form a control, u_(out), as a combination of the string. Forinstance, a weighted average of the possible control signals, u_(se),can be used to calculate the control, u_(out), although other methods ofcombining the string can also be implemented. In some embodiments, thecombination may be based on estimated system outputs, y_(est_se), foreach of the possible control signals, u_(se), similar to the way inwhich a topology is selected in the selector and combiner mentionedearlier. These estimated system outputs, y_(est_se), can be found via anestimation portion of the nonlinear model, for instance, using Model 1:

y _(est_se) =W _(m) {u _(se),Θ}

Where the estimated model parameter tensor, Θ, is found in the lookuptable based on the measured system output, y_(meas), and the control,u_(out), both from a previous iteration.

In an embodiment, the slide mode predictor 1409 can produce theestimated system output, y_(est_SE). More specifically, the system modelor nonlinear model can be provided with a control portion, forgenerating possible control signals, u_(se), and an estimation portionfor estimating estimated system outputs, y_(est_se). A time-varyinglinear system, W_(m), can make up a foundation of either the estimationportion or the control portion, and can be bifurcated or split into asum of a linear and a nonlinear portion and the control timeline can besplit into frames of differing lengths (or number of control samples oradaptation iterations) with some processing of the nonlinear modeloccurring on a CPU or other slower resource and real-time aspects of thenonlinear model occurring on an FPGA or other faster resource. A currentframe can be supplied with a structure of the time-varying linearsystem, W_(m). As noted relative to FIG. 43 , the nonlinear portion ofthe time-varying linear system, W_(m), is effectively an unknown errorand thus not used or considered in the processing (other than in attemptto minimize this error). The structure of the time-varying linearsystem, W_(m), can be pre-processed, for instance on a CPU, though itcan also be accessed from an empirically-derived lookup table. Thestructure of the time-varying linear system, W_(m), remains constantthrough the current frame. Yet, since the time-varying linear system,W_(m), is also dependent on the estimated model parameter tensor, Θ, theestimation portion of the nonlinear model adapts within a frame as Θchanges in the FELB 1404 (as the adaptive engine modifies Θ to minimizean error relative to measured system behavior). This can involvecalculating an estimation error, ê, or cost function, J, based on two ormore of (1) measured system outputs, y_(meas), from a previousiteration, (2) estimated system outputs, y_(est_se), from a previousiteration, and (3) reference signal, r. Adaption can then involveapplying an estimation law to at least the reference signal, r, and theestimation error, ê, or cost function, J, to estimate an estimated modelparameter tensor, Θ. The estimated model parameter tensors, Θ, can thenbe tested in the TFPA sub-engine 1405, and adaptation can continuethrough the entirety of the frame, and in turn, W_(m), is adaptedthroughout the frame (or until convergence is achieved). Once a frame iscomplete the method selects a next frame and a new structure of thetime-varying linear system, W_(m), is provided into the model andadaptation of the estimated model parameter tensor, Θ, is carried outthrough this next frame until convergence. As noted earlier, thestructure of the time-varying linear system, W_(m), can include thestructure of the A, B, and C matrices that are part of the system ofequations making up W_(m).

The Adaptive Proportional Integral Derivative (PID) Sub Engine

As noted above, in some control law modules (e.g., control law modules506), more than one control law can be implemented. Some non-limitingexamples of which include the TARC control law module/sub-engine and theAdaptive PID control law module. Various aspects of the TARC control lawmodule/sub-engine have been discussed above, including at least inrelation to FIGS. 11-13 . The following sections discuss the AdaptivePID control law module/sub-engine, its structure and sub-components,algorithm/methods of operation, and control law(s) implemented in theAdaptive PID sub-engine.

PID controllers can be implemented using various different tuning rules(also known as PID tuning rules) and operator tuning methods. Thesetuning methods and rules are fairly accurate and powerful when theunderlying model characterization they are based on is accurate for theduration of operation of a specific PID control law. Typically, PIDcontrol laws are characterized for relatively simple linear systems withdelays, rather than the highly non-linear/chaotic systems (e.g., plasmaprocessing chambers) generally discussed in this disclosure. Aspects ofthe disclosure are directed to an Adaptive PID control lawmodule/sub-engine that is designed to consolidate the use of PID controllaws in non-linear systems. This approach, described in further detailbelow, assumes that at any single time instant (i.e., snapshot of time),the non-linear system being controlled can be modeled by a system model(e.g., a estimation portion, a non-linear model) for which PID tuningcontrol laws are available. In some cases, this assumption may be validfor a sufficient duration of time such that the PID tuning control lawis applicable for the whole duration (e.g., for the whole frame) of thatsystem model. Additionally, the adaptive PID control law sub-engineand/or the estimation law module associated with the control lawsub-engine is configured to incorporate/model the system'snon-linearities in the parametric/linear model, W_(m), of the system. Insome examples, the dynamic structure of the parametric/linear model maybe fixed for the duration of the PID tuning control law. Further, thesystem's non-linearities are included in the linear model (W_(m))through the time varying/changing nature of the plurality ofcoefficients forming the parametric/linear model. In some embodiments,these time-varying coefficients (e.g., a_(est), b_(est)) and/ortime-varying parameters (e.g., θ) may be adapted, which serves toadaptively change the control output (e.g., possible control signal)produced by the adaptive PID control law module. Such a design helpsensure that the controller reacts to the non-linearities in accordancewith the arbitrary waveform (e.g., reference waveform) specified by theuser.

FIG. 16 illustrates a block diagram 1601 of an adaptive PID controlsystem, in accordance with one or more implementations. As seen, theadaptive PID control system in FIG. 16 comprises an adaptive PIDcontroller 1606, a feed forward module 1619, and a plurality of summers.The adaptive PID control system receives as input the reference waveform(or reference signal), r, and the measured system output, y_(meas). Theadaptive PID control system includes a feedback path (i.e., throughwhich the measured system output is received) and a feedforward path,where the feedforward path includes the feed forward module 1619. At thefirst summer (on the left of the page), a measurement error, ê, iscalculated based on a difference between the reference signal, r, andthe measured system output, y_(meas). For example, the measurement error(or simply error) is calculated as: |r−y_(meas)|. This measurementerror, ê, is passed to the PID controller 1606 for further processing.The PID controller 1606 is configured to calculate a first possiblecontrol signal (also referred to as a possible PID control signal),u_(p), which is then passed to the second summer (on the right of thepage). In some cases, the reference waveform/signal is also passed tothe feed forward module 1619, which processes the reference waveform toproduce a second possible control signal (or possible feed forwardcontrol signal), u_(FF). This possible feed forward control signal,u_(FF), is also passed to the second summer, which outputs a possiblecontrol signal, u_(SE), based on computing a difference between u_(P)and u_(FF). In other words, the possible control signal, u_(SE), outputby the adaptive PID control law module/sub-engine may be representedusing Control Law 4 as follows:

u _(se) =u _(PID) _(k) −u _(FF) _(k) =[θ,θ₇][ω,ω₇]  (Control Law 4)

FIG. 17A illustrates an example of a method 1701-a for controlling anon-linear system using an adaptive PID control module. The operationsof method 1701-a presented below are intended to be illustrative. Insome implementations, method 1701-a may be accomplished with one or moreadditional operations not described, and/or without one or more of theoperations discussed. Additionally, the order in which the operations ofmethod 1701-a are illustrated in FIG. 17A and described below is notintended to be limiting.

In some implementations, method 1701-a may be implemented in one or moreprocessing devices (e.g., a central processing unit or CPU, a digitalprocessor, an analog processor, a digital circuit designed to processinformation, an analog circuit designed to process information, a statemachine, a field programmable gate array or FPGA, and/or othermechanisms for electronically processing information). The one or moreprocessing devices may include one or more devices executing some or allof the operations of method 1701-a in response to instructions storedelectronically on an electronic storage medium. The one or moreprocessing devices may include one or more devices configured throughhardware, firmware, and/or software to be specifically designed forexecution of one or more of the operations of method 1701-a.

In some embodiments, the PID tuning control law (or simply, PID controllaw) may be represented as follows:

u _(k)=θ₁ r _(k)+θ₂Σ_(j=1) ^(k) r _(j)+θ₃ H{r _(k)}+θ₄ y _(k)+θ₅Σ_(j=1)^(k) y _(j)+θ₆ H{y _(k)}  (Equation 37)

In Equation (37), r_(k) is the reference signal/waveform at time ‘k’,y_(meas) is the measured system output that is feedback to the input attime ‘k’, and u_(SE) is the possible control signal for the currentiteration. This possible control signal, u_(SE), along with one or moreother possible control signals from one or more other control lawsub-engines/modules is passed to the selector module, which then selectsone of (or a combination of) the possible control signals as the controloutput for the current iteration ‘k’.

In some examples, equation (37) may be represented in estimator form as:

u _(k)=θω, where ω=[r _(k),Σ_(j=1) ^(k) r _(j) ,H{r _(k) },y_(k),Σ_(j=1) ^(k) y _(j) ,H{y _(k)}]

As described above, the tensor ω is also referred to as the inputregressor. It should be noted that, the input regressor tensor, ω,discussed in relation to the adaptive PID sub-engine may be similar orsubstantially similar to the input regressor tensor, ϕ, discussed inrelation to some of the other control law modules/sub-engines.

The adaptive PID controller (e.g., shown as PID controller 1606 in FIG.16 ) implements one or more of the process/non-linear/parametric/linearmodel of the one or more actuators and/or the non-linear systemcontrolled by the one or more actuators. In some examples, the modelparameter tensor, θ, estimated by the estimation module (e.g.,estimation module or FELB 1804 in FIG. 18 ) may be mapped to the processmodel and/or the tuning laws of the adaptive PID controller. Onenon-limiting example of the PID control system structure includes thetwo-degrees of freedom filtered derivative PID controller describedabove in relation to FIG. 15 . Other PID control system architecturesknown or contemplated in the art may be utilized in differentembodiments, and the example discussed herein is not intended to belimiting.

In some cases, the possible feed forward control signal, u_(FF),produced by the feed forward module 1519 may be written using equation(38) shown below:

$\begin{matrix}{u_{{FF}_{k}} = {{\alpha K_{C}r_{k}} + {\left\lbrack {{\alpha K_{C}\frac{T_{d}}{N}} + {\beta K_{C}T_{d}}} \right\rbrack H\left\{ r_{k} \right\}} - {\frac{T_{d}}{N}H\left\{ u_{{FF}_{k - 1}} \right\}}}} & \left( {{Equation}38} \right)\end{matrix}$

Additionally, the possible PID control signal, u_(PID), produced by thePID controller 1506 may be calculated using equation (39):

$\begin{matrix}{u_{{PID}_{k}} = {{\left\lbrack {K_{C} + {\frac{K_{C}}{T_{i}}\left( \frac{T_{d}}{N} \right)}} \right\rbrack e_{k}} + {\frac{K_{C}}{T_{i}}{\sum}_{j = 1}^{k}e_{j}} + {{K_{C}\left( \frac{T_{d}}{N} \right)}\left( {N + 1} \right)H\left\{ e_{k} \right\}} - {\frac{T_{d}}{N}H\left\{ u_{{PID}_{k - 1}} \right\}}}} & \left( {{Equation}39} \right)\end{matrix}$

In some cases, e_(k) may be represented as the difference between thereference signal/waveform and the measured system output. That is,e_(k)=r_(k)−y_(meas_k). Further, the controller parameters (e.g., α,K_(C), T_(d), N, β, T_(i), etc.) may be determined based on PID tuningcontrol law(s). In some embodiments, these PID tuning control law(s) maybe synthesized from experiments and stored in memory as a look-up table,or another applicable data structure. In some cases, the controllerparameters may be defined using Equations 40-45 shown below:

α=f ₁(a _(est) ,b _(est),τ_(m)),  (Equation 40)

K _(C) =f ₂(a _(est) ,b _(est),τ_(m)),  (Equation 41)

τ_(d) =f ₃(a _(est) ,b _(est),τ_(m)),  (Equation 42)

N=f ₄(a _(est) ,b _(est),τ_(m)),  (Equation 43)

β=f ₅(a _(est) ,b _(est),τ_(m)),  (Equation 44)

T _(i) =f ₆(a _(est) ,b _(est),τ_(m))  (Equation 45)

Further, [PID+FF]_(6,n) =f(a _(est) ,b _(est),τ_(m))  (Equation 46)

In Equations 40-45, a_(est) and b_(est) are the estimated coefficientsof the non-linear/parametric/process model and τ_(m) is the processdelay. In some examples, the process delay, τ_(m), may bedetected/estimated as described in co-owned U.S. application Ser. No.17/685,931, the entire contents of which are incorporated herein byreference in their entirety.

In some embodiments, the plurality of sub-components, θ₁, θ₂, θ₃ . . .θ₇, of the estimated model parameter tensor, [θ], may be written asfollows:

$\begin{matrix}{\theta_{1} = {\left\lbrack {K_{C} + {\frac{K_{C}}{T_{i}}\frac{T_{d}}{N}}} \right\rbrack - {\alpha K_{C}}}} & \left( {{Equation}47} \right)\end{matrix}$ $\begin{matrix}{\theta_{2} = \left\lbrack \frac{K_{C}}{T_{i}} \right\rbrack} & \left( {{Equation}48} \right)\end{matrix}$ $\begin{matrix}{\theta_{3} = {\left\lbrack {K_{C}\frac{T_{d}}{N}\left( {N + 1} \right)} \right\rbrack - \left\lbrack {{\alpha K_{C}\frac{T_{d}}{N}} + {\beta K_{C}T_{d}}} \right\rbrack}} & \left( {{Equation}49} \right)\end{matrix}$ $\begin{matrix}{\theta_{4} = {{- \left\lbrack {K_{C} + {\frac{K_{C}}{T_{i}}\frac{T_{d}}{N}}} \right\rbrack} = {{\alpha K_{C}} - \theta_{1}}}} & \left( {{Equation}50} \right)\end{matrix}$ $\begin{matrix}{\theta_{5} = {{- \left\lbrack \frac{K_{C}}{T_{i}} \right\rbrack} = {- \theta_{2}}}} & \left( {{Equation}51} \right)\end{matrix}$ $\begin{matrix}{\theta_{6} = {- \left\lbrack {K_{C}\frac{T_{d}}{N}\left( {N + 1} \right)} \right\rbrack}} & \left( {{Equation}52} \right)\end{matrix}$ $\begin{matrix}{\theta_{7} = {- \frac{T_{d}}{N}}} & \left( {{Equation}53} \right)\end{matrix}$

Further, the estimated model parameter tensor [θ] may be represented bythe concatenation of its sub-components. That is, the estimated modelparameter tensor [θ]produced by the estimation law module 1804 may berepresented as [θ₁ . . . θ₇]. In some examples, the possible controlsignal, u_(SE), produced by the adaptive PID control law module 1805 maybe calculated from the possible PID control signal, u_(PID), and thepossible feed forward control signal, u_(FF). Similar in line with someof the other sub-engines described herein, the possible control signal,u_(SE), may be a function of the estimated model parameter tensor [θ]and the input regressor, ω. The input regressor, ω, may also comprise aplurality of subcomponents (e.g., 7 subcomponents, ω₁ . . . ω₇).Further, each sub-component (e.g., θ₁) of the estimated model parametertensor may be multiplied by a corresponding sub-component (e.g., oi) ofthe input regressor to determine a subcomponent of the possible controlsignal. In other words, the possible control signal, u_(SE), may becalculated as: u_(SE) [θ₁ . . . θ₇][ω₁ . . . ω₇], whereω₇=H{u_(out_k−1)}. That is, ω₇ is determined from filtering the controloutput, u_(out_k−1), from the previous iteration.

In some examples, the adaptive PID control law module may be implementedusing two different mechanisms/schemes. In some examples, the adaptivePID control law module 1805 may comprise a first control law module(e.g., a Control Then Output Estimation or CTOE module) and a secondcontrol law module (e.g., an Output Estimation Then Control or OETCmodule). In some cases, the PID control law module 1805 is made adaptive(e.g., as a result of adapting/changing the estimated model parametertensor, θ, at each iteration) and integrated into the adaptive engine(e.g., adaptive engine 500 in FIGS. 5A-5C, adaptive engine 800 in FIGS.8A-B). The possible control signals produced by each of the CTOE andOETC control law modules 1600 and 1700, respectively, may be passed to acontrol selector and combiner (CSC) 1826 of the sub-engine 1805, whichselects one of (or a combination of) the control signals as the possiblecontrol signal, u_(SE), for the adaptive PID sub-engine 1805. In someaspects, the CSC 1826 may be similar or substantially similar to the CSC1107 of the TARC sub-engine, which is configured to select one of (or acombination of) the possible control signals from the adaptive inversecontrol laws module 1114, the eigen control laws module 1124, and thepenalty control laws module 1134.

Said another way, the adaptive engine (e.g., a selector module) mayselect one or combination of possible control signals, u_(se), that leadto a control, u_(out), that causes a measured system output, y_(meas),that is close to the total estimated system output, y_(est_out), or thereference signal, r. This may involve an error or cost function thatcompares the measured system output, y_(meas), for a previous iteration,or the reference signal, r, to the total estimated system outputs,y_(est_out), calculated for various possible topologies. Morespecifically, the TSD 1818 may analyze a cost function, such as Equation4, to select an optimal possible control signal, u_(se), or combinationof possible control signals, u_(se) (in the form of a topology forcombining the possible control signals)

Returning to FIG. 17A, which depicts an example of a method flow 1701-aimplemented by way of a CTOE control law module 1600, in accordance withone or more implementations. In some embodiments, the method flow 1701-a(also referred to as the CTOE method 1701-a) is based at least in parton directly estimating the model parameter tensor, θ. Specifically, theCTOE method depicted in FIG. 17A comprises determining thenon-linear/parametric/process model based on PID tuning rules and directestimation of the subcomponents (e.g., [θ₁ . . . θ₇]) of the modelparameter tensor, θ.

As seen, a first operation (1702) comprises receiving at least onesystem output measurement, y_(meas). The system output measurement,y_(meas), may be received at the estimation law module/FELB 1804. Asecond operation (1704) comprises accessing one or more previouslyestimated system output, y_(est_SE). In some cases, the estimation lawmodule or another component of the adaptive engine accesses ‘k−1’previous estimates of the system output. A third operation (1706)comprises computing one or more estimation errors or a cost function,where the estimation errors/cost functions are based at least in part oncomparing the system output measurement, y_(meas), with one or moreprevious estimates of the system output. A fourth operation (1708)comprises estimating one or more model parameter tensors, θ, based atleast in part on computing the estimation errors at operation (1706). Afifth operation (1710) comprises estimating a delay, τ_(est). A sixthoperation (1712) comprises computing a possible control signal for theCTOE control law module using the one or more estimated model parametertensors, θ, and an input regressor, ω. A seventh operation (1714)comprises mapping the estimated model parameter tensors, θ, to aplurality of controller parameters. The controller parameters may besimilar or substantially similar to the ones described in relation toFIGS. 15-21 . An eighth operation (1716) comprises mapping thecontroller parameters to a plurality of coefficients (e.g., a_(est),b_(est)) of the non-linear/parametric/process model. A ninth operation(1718) comprises estimating or adapting the model based at least in parton the mapping 1716. A tenth operation (1720) comprises estimating thesystem output, y_(est_SE), for the CTOE control law module 1600 based atleast in part on applying the possible control signal, u_(SE), Computedat 1712 to the estimated process model.

FIG. 17B illustrates an example of a method 1701-b for controlling anon-linear system using an adaptive PID control module. The operationsof method 1701-b presented below are intended to be illustrative. Insome implementations, method 1701-b may be accomplished with one or moreadditional operations not described, and/or without one or more of theoperations discussed. Additionally, the order in which the operations ofmethod 1701-b are illustrated in FIG. 17B and described below is notintended to be limiting.

In some implementations, method 1701-b may be implemented in one or moreprocessing devices (e.g., a central processing unit or CPU, a digitalprocessor, an analog processor, a digital circuit designed to processinformation, an analog circuit designed to process information, a statemachine, a field programmable gate array or FPGA, and/or othermechanisms for electronically processing information). The one or moreprocessing devices may include one or more devices executing some or allof the operations of method 1701-b in response to instructions storedelectronically on an electronic storage medium. The one or moreprocessing devices may include one or more devices configured throughhardware, firmware, and/or software to be specifically designed forexecution of one or more of the operations of method 1701-b.

Broadly, FIG. 17B depicts an example of a method flow 1701-b implementedby way of a OETC control law module (e.g., OETC control law module 1700in FIGS. 18 and 20 ), in accordance with one or more implementations. Asseen, a first operation (1721) comprises receiving at least one systemoutput measurement, y_(meas). The system output measurement, y_(meas),may be received at the estimation law module/FELB 1804. A secondoperation (1722) comprises accessing one or more previously estimatedsystem outputs, y_(est_SE). In some cases, the estimation law module oranother component of the adaptive engine accesses ‘k−1’ previous systemoutput estimates. A third operation (1723) comprises computing one ormore estimation errors, where the estimation errors are based at leastin part on comparing the system output measurement, y_(meas), with oneor more previous estimates of the system output. A fourth operation(1724) comprises determining a model order (e.g., 1^(st) order, 2^(nd)order, etc.) corresponding to a lowest estimation error, wheredetermining the model order is further based on the previous estimatesof the system output and the system output measurement, y_(meas). Insome cases, determining the model order is also based on an estimate ofthe delay, τ_(est) (fifth operation 1725). A sixth operation 1726comprises estimating one or more model parameter tensors, θ. A seventhoperation 1728 comprises estimating a system output, y_(est_SE), basedat least in part on the one or more estimated model parameter tensors,θ. An eighth operation 1727 comprises mapping the one or more estimatedmodel parameter tensors, θ, to one or more coefficients (e.g., a_(est),b_(est) discussed above) of the non-linear/parametric/process model.Further, a ninth operation 1729 comprises computing the control signals,u_(PID) and u_(FF), based at least in part on the coefficients of theprocess model, a_(est), b_(est), and the estimated delay, τ_(est). Atenth operation 1730 comprises computing the possible control signal,u_(SE), from the control signal, u_(PID) and u_(FF). As described abovein relation to FIG. 16 , the possible control signal, u_(SE), for theadaptive PID sub engine may be calculated from a difference between thecontrol signal (u_(PID)) and the feed forward control signal (u_(FF)).That is, u_(SE)=u_(PID)−u_(FF). In some other cases, the possiblecontrol signal, u_(SE), may be calculated by summing the u_(PID) andu_(FF) control signals. In such cases, u_(SE)=u_(PID)+u_(FF).

FIG. 19 depicts an adaptive engine 1900 showing the details of the CTOEcontrol law module 1600 of the adaptive PID sub-engine, according tovarious aspects of the disclosure. As seen, the adaptive engine 1800comprises an estimation law module (or FELB) 1804, an adaptive PIDsub-engine 1901, and a delay detector/estimator 1932. Further, theadaptive PID sub-engine 1901 comprises a CTOE control law module 1906, atensor mapping module 1902, an estimated output mapping module 1903, andan inverse mapping module 1933. The inverse mapping module 1933 isconfigured to calculate F⁻¹(θ) based on the parametric/process modeltype and/or order (e.g., 1^(st) order, 2^(nd) order, N, order). In somecases, the term “parametric/process model type” implies the presence ofa delay in the process model. The adaptive engine 1800 further comprisesa NL compensation module 1913 configured to compensate fornon-linearities in one or more of the control signal (e.g., u_(desired))and the estimated system output (e.g., y_(est_PID)) received from theadaptive PID sub-engine. In one non-limiting example, the NLcompensation module 1913 may be implemented using a plurality of NLtransfer functions.

Similar to some of the other adaptive engines described herein, theestimation law module/FELB 1804 is configured to receive an inputregressor, where the input regressor comprises at least a referencewaveform (also referred to as setpoint stream, reference signal, or aseries of set points) denoted as ‘r’, and a system output measurement,y_(meas). In some embodiments, the input regressor may additionallycomprise one or more of a total estimated system output for a previousiteration, y_(est_out_k−1), an estimated delay, τ_(m_est), a controloutput for a previous iteration, u_(out_k−1), an estimation error, ê,the non-linear model, W_(m), and a plurality of coefficients for thenon-linear model.

In some examples, the estimation law module 1804 is configured to applyone or more estimation laws to the input regressor, ω, to produce one ormore estimated parameter tensors, θ, for a non-linear model of the oneor more actuators and/or the system controlled by the one or moreactuators. The estimation law module 1804 passes the one or moreestimated parameter tensors, θ, to the control law module 1906 of theadaptive PID sub-engine. In some examples, the control law module 1906also receives at least a portion (e.g., one or more subcomponents) ofthe input regressor. The control law module 1906 computes a controlsignal given by u_(desired)=θω. This control signal, u_(desired), ispassed to the NL compensation module 1913 where it is further processedto compensate for non-linear effects before being passed to the CSC(e.g., shown as CSC 1826 in FIG. 18 ).

In some examples, the estimation law module 1804 may optionally send theestimated model parameter tensors, θ, to the tensor mapping module. Thetensor mapping module also receives the estimated process delay,τ_(m_est), from the delay detector/estimator 1932. In some examples, theinverse mapping module 1933 receives as input the estimated modelparameter tensors, θ, and the estimated process delay, τ_(m_est), andoutputs a tensor comprising the plurality of controller parameters(e.g., a, K_(C), τ_(d), N, 3, τ_(i), etc.) to the tensor mapping module.Specifically, the inverse mapping module 1933 is used to map theestimated model parameter tensors, θ, to the plurality of controllerparameters, where the mapping from the estimated model parameter tensorsto the controller parameters is based on one or more of the estimationerror, ê, and the estimated process delay.

As noted above, each of the plurality of controller parameters may berepresented as a function of the estimated coefficients (e.g., a_(est),b_(est)) of the non-linear/parametric/process model and the estimatedprocess delay. In some cases, the tensor mapping module is configured tomap the controller parameters (e.g., received from the inverse mappingmodule 1933) to the estimated coefficients of the process model. In someaspects, at least a portion of the non-linear/parametric/process modelis estimated at the tensor mapping module, based upon mapping thecontroller parameters to the coefficients of the process model. Thetensor mapping module passes information pertaining to the estimation ofthe process model, the estimated coefficients of the process model, andany other relevant information to the Estimated Output Mapping Module1903. The Estimated Output Mapping Module 1903 is configured to producea possible estimated system output, y_(est_PID), for the CTOE controllaw module, based upon applying (1) a previous iteration of the possiblecontrol signal, u_(SE_k−1), or (2) the control signal, u_(desired), tothe non-linear/process model. This possible estimated system output,y_(est_PID), corresponding to the CTOE control law module is passed tothe NL transfer functions 1913, which compensates for any non-lineareffects present in the y_(est_PID) signal. After compensating fornon-linear effects (if any) in the y_(est_PID) signal, the NLcompensation module/transfer functions 1913 passes the possibleestimated system output (e.g., y_(est_SE_CTOE)) corresponding to theCTOE control module 1600 to the control selector/combiner (e.g., CSC1826).

FIG. 20 depicts a block diagram 2000 showing how the control law isimplemented for the CTOE method, according to various aspects of thedisclosure. As seen, FIG. 20 illustrates a tensor concatenate module2011 and the CTOE control law module 1906 (previously described inrelation to FIG. 19 ). The tensor concatenate module 2011 and the CTOEcontrol law module 1906 may be embodied in hardware, software, or acombination thereof. As seen, the tensor concatenate module 2011 isconfigured to receive the plurality of subcomponents (e.g., θ₁, θ₂, θ₃ .. . θ₇) of the estimated model parameter tensor, θ, from the estimationlaw module 1804. In some examples, the tensor concatenate module 2011also receives the plurality of subcomponents (e.g., ω₁, ω₂, ω₃ . . . ω₇)of the input regressor, ω. The tensor concatenate module 2011 isconfigured to concatenate the inputs (e.g., θ₁ . . . θ₇; ω₁ . . . ω₇)and pass them to the CTOE control law module 1906, which produces thecontrol signal, u_(desired)=[θ][ω]. In some examples, the controlsignal, u_(desired), may also be represented as u_(PID)−u_(FF).Alternatively, the control signal, u_(desired), may be calculated asu_(PID)+u_(FF).

As seen, in some examples, one of the subcomponents (ω₇) of the inputregressor, corresponding to the control output, u_(out_k−1), from theprevious iteration, is in the feedback path, where the feedback pathcomprises a 1-sample delay. In such cases, the previous iteration'scontrol output, u_(out_k−1), is delayed by 1-sample before being passedto the tensor concatenate module 2011.

FIG. 21 depicts a block diagram of an adaptive engine 2100, showing adetailed view of the OETC control law module of the adaptive PIDsub-engine, according to various aspects of the disclosure. The adaptiveengine 2100 in FIG. 21 implements one or more aspects of the adaptiveengine 1800 previously described in relation to FIG. 18 . The adaptiveengine 2100 comprises an estimation law module/FELB 1804, an OETCcontrol law module 2121, a delay detector/estimator 1932, a NLcompensation module 1913 (also referred to as NL transfer functions1913), a control selector/combiner or CSC 2116, and a selector module2108. The NL transfer functions 1913, the CSC 2116, the delaydetector/estimator 1932, and the selector module 2108 may be similar orsubstantially similar to the ones described above in relation to FIGS.18-20 . While not shown, the selector module 2108 may also comprise aCSC (e.g., shown as CSC 1816 in FIG. 18 ) and one or more of a TSD(e.g., TSD 1818) and a tensor sync and coherency module (e.g., tensorsync module 1827).

In some embodiments, the OETC control law module comprises a control law2106 block and a non-linear/estimation portion block (shown by thedashed lines). As seen, the control law 2106 may form a portion of thenon-linear/estimation portion, in some examples. The OETC control lawmodule further comprises a process model definitions and order mapper(PMDOM) 2131, a parameter mapping module 2132, a model order mapper tooutput estimation (MOMOE) 2133.

In the example shown, the estimation law module 1804 receives as inputthe reference waveform, r, the system output measurement, y_(meas), theestimated delay, τ_(m_est), and the non-linear/estimation portion,W_(m). The estimation law module 1804 may also receive the model order(M_(i)) from the PMDOM 2131. In one non-limiting example, the modelorder may be equal to or less than 5. It should be noted that, highermodel orders (e.g., >5) are contemplated in different embodiments, andthe examples listed herein are not intended to be limiting. In somecases, the process model selected may be based on the hardware resourcesavailable. For example, a process model having zeros and a delay of lessthan or equal to order 5 (i.e., a 5^(th) order model), may be utilized,based on the hardware resources available.

In some embodiments, the process models used for the OETC method/schemefor which the estimated model parameters can be translated into PIDtunable values (i.e., where the PID tunable values are given as afunction of the estimated model parameters) may be represented asfollows:

$\begin{matrix}{{{M_{1}:y} = {\left( {K_{n}z^{{- k}\tau_{m}}} \right)u_{out}}},{{{where}k_{\tau m}} = {{ceiling}\left( \frac{\tau_{m}}{T_{s}} \right)}}} & \left( {{Equation}55} \right)\end{matrix}$ $\begin{matrix}{{M_{2}:y} = \left( {K_{n} \pm {K_{n}H\left\{ u_{out} \right\} z^{{- k}\tau_{m}}}} \right.} & \left( {{Equation}56} \right)\end{matrix}$ $\begin{matrix}{{M_{i}:{\overset{.}{x}}_{est}} = {{\begin{bmatrix}{- a_{4}} & {1\ldots} & 0 \\ \vdots & \ddots & \vdots \\{- a_{0}} & {0\ldots} & 0\end{bmatrix}x_{est}} + {\begin{bmatrix}b_{4} \\ \vdots \\b_{0}\end{bmatrix}u_{out}z^{{- k}\tau m}}}} & \left( {{Equation}57} \right)\end{matrix}$ $\begin{matrix}{y_{est} = {\begin{bmatrix}1 & \ldots & 0 \\ \vdots & \ddots & \vdots \\0 & \ldots & 1\end{bmatrix}x_{est}}} & \left( {{Equation}58} \right)\end{matrix}$

In accordance with aspects of the disclosure, the OETC control law canbe implemented in 4 or less reduced instruction set computer (RISC)clock cycles, in some embodiments. This means that, if the control rate(T_(s)) is ˜250 ns and the real-time processor (e.g., FPGA or ASIC) hasa clock rate (T_(clock)), where T_(clock)=T_(s)/8=31.25 n_(s), thecontroller can be implemented through an oversampling factor of 2, whichserves to reduce consumption by a factor of 2, through pipelining,resource sharing and streaming, etc.

In some other cases, if the control rate is set to T_(s)=4*T_(clock)=125ns, the controller can be twice as fast. In other words, the presentdisclosure supports the u_(se) of a variable control rate (e.g.,Ts=4*T_(clock); T_(s)=8*T_(clock)) based on the hardware resourcesavailable. In some cases, if the hardware resources are limited, theresource usage can be divided (e.g., by a factor of 2, such thatT_(s)=8*T_(clock)), which allows pipelining and sharing of hardwareresources.

Although not illustrated, the Adaptive PID sub-engine can operate as astandalone controller. In such an embodiment, the estimation lawmodules/FELB can be replaced by an empirically derived lookup table forthe estimated model parameter tensors, Θ. More specifically, a lookuptable can be empirically formed as a mapping between (1) y_(meas) andu_(out) from a reference/calibration system and (2) estimated modelparameter tensors, Θ. During operation of the Adaptive PID standalonecontroller as a standalone controller, a control, u_(out), can beprovided to the one or more actuators, and measurements, y_(meas), canbe taken from the one or more actuators and/or system. These can then beused to select estimated model parameter tensors, Θ, from the lookuptable, and then provided to the Adaptive PID standalone controller todetermine what will be called a control signal, u_(out). This controlsignal, u_(out), can be provided to the one or more actuators.Alternatively, the Adaptive PID standalone controller can produce astring of possible control signals, u_(se), and form a control, u_(out),as a combination of the string. For instance, a weighted average of thepossible control signals, u_(se), can be used to calculate the control,u_(out), although other methods of combining the string can also beimplemented. In some embodiments, the combination may be based onestimated system outputs, y_(est_se), for each of the possible controlsignals, u_(se), similar to the way in which a topology is selected inthe selector and combiner mentioned earlier. These estimated systemoutputs, y_(est_se), can be found via an estimation portion of thenonlinear model, for instance, using Model 1:

y _(est_se) =W _(m) {u _(se),Θ}

Where the estimated model parameter tensor, Θ, is found in the lookuptable based on the measured system output, y_(meas), and the control,u_(out), both from a previous iteration.

The Adaptive Tensor Identity Mapping Sub Engine (ATIMC)

As noted above, when there is not a-priori knowledge about the systemdynamics and where large disturbances exist (e.g., an abrupt change inprocess chemistry or changing chamber pressure, gas flow, or thermalconditions or anything that would cause a large change in plasmaimpedance), or where the system is oscillatory, a fifth sub-engine, theATIMC sub-engine can be implemented, selected or have the most influenceon the control, u_(out). The ATIMC sub-engine creates a control law indifferent parts by subtracting specific effects of disturbances,nonlinearities, dither, and noise in a compartmentalized manner ratherthan lumping these together. In other words, the ATIMC sub engine isconfigured to separate between disturbance rejection, noise canceling,and the controller itself, while at the same time able to track/followthe reference signal (or setpoint) adaptively and robustly. In someexamples, the ATIMC sub engine is designed to support multi-rate signalprocessing, which allows for faster and more robust adaptation, ascompared to the prior art. Additionally, or alternatively, the ATIMC subengine may also help reduce or minimize control signal noise (e.g.,noise associated with the possible control signal, u_(SE), or the outputcontrol signal, u_(out)). The ATIMC sub engine is configured to producepossible control signals, u_(SE), that can be used for controllingnon-linear systems having stable or unstable zero-dynamics.Additionally, the ATIMC sub engine may also be utilized for controllingstable or unstable non-linear systems. In some embodiments, the ATIMCsub engine may be utilized to produce control signals for non-linearmultiple input multiple output (MIMO) systems. Additionally, the ATIMCsub engine may be used in conjunction with Artificial Neural Networks(ANN) and/or Fuzzy Logic Mechanisms (FLM), in some embodiments.

The ATIMC sub engine (or ATIMC control law module) is configured to workwith one or more of the estimation law modules (or FELBs) describedherein. For example, the ATIMC sub engine may be incorporated within anadaptive engine (e.g., adaptive engine 500), where the adaptive engineprovides a plurality of combinations of estimation law modules (alsoreferred to as FELBs) and the ATIMC control law module.

FIG. 23 illustrates an example of an adaptive engine 2300, in accordancewith one or more implementations. As seen, the adaptive engine 2300comprises an estimation law module 2304 (also referred to as FELB 2304),an ATIMC sub engine 2305, and a selector module 2308. The selectormodule 2308 may be similar or substantially similar to any of the otherselector modules described herein, including at least selector module508. As seen, the selector module 2308 receives one or more possiblecontrol signals, u_(SE), from the control law module/sub engine 2305 andthe other sub-engines/laws 2315 and selects one or a combination ofthese possible control signals, u_(SE), for output as the control,u_(out). In the example shown, sub engine 2305 comprises a plurality ofinternal mechanisms/modules, where each internal mechanism or module isconfigured to compensate for different physical effects, noise,disturbance, etc. For instance, the sub engine 2305 comprises anAdaptive Adjustment Mechanism (AAM) module 2355 that helps determine atevery time instant, k, the coefficients of the estimated model parametertensor, θ, that are relayed to different mechanisms/modules of the subengine.

In some examples, a tensor, ω, comprising a plurality of subcomponents(e.g., ω_(u_des), ω_(uin), ω_(uζ), ω_(uout), etc.) is received by theAAM module 2355. The subcomponents of the ω tensor correspond todifferent physical quantities, signals, physical effects (e.g., noiseand disturbance), etc. Here, the ω tensor is being used as the inputregressor tensor, ⊙, or a filtered variation thereof (e.g., ψ) describedin the preceding sections. As shown, the estimation law module/FELB 2304receives the input regressor tensor, ⊙, from the sub engine 2305. TheFELB 2304 also receives one or more error signals (or a tensor of errortensors, [e]) from the sub engine 2305, generates one or more estimatedmodel parameter tensors, θ, and passes the model parameter tensors, θ,to the sub engine. In some examples, the FELB 2304 also passes aderivative of the estimated model parameter tensors, {dot over (θ)}, tothe sub engine. In FIG. 23 , the notation [θ] is used to indicate thepresence of one or more of θ and its derivative {dot over (θ)}.

The first letter of the subscript (e.g., ‘u’, ‘y’, etc.) of an ωvariable/signal in FIGS. 23-30 is used to indicate whether the ωvariable/signal corresponds to a control signal, a measurement, etc. Insome cases, the AAM module 2355 processes the subcomponents of the ωtensor to generate the one or more error tensors, [e], sent to theestimation module 2304. For instance, as seen in FIG. 23 , the AAMmodule 2355 receives a plurality of subcomponents (e.g., ω_(u_out),ω_(y_meas), Ω_(y_nd), θ_(u_des), ω_(uζ)) of the ω tensor, where somesubcomponents (e.g., ω_(u_out), ω_(u_des)) are associated with controlsignals, some subcomponents (e.g., ω_(y_meas), ω_(y_nd)) are associatedwith system measurements, etc. The sub engine 2305 also includes aplurality of filters, denoted as H{·}, including H_(y){·}, H_(K){·},H_(ζ){·}, H_(Ω){·}, etc. Each of these filters receives a signal (e.g.,control output, u_(out); system output measurement, y_(meas); referencesignal, r; etc.) and outputs a corresponding subcomponent of the ωtensor. For instance, the filter represented by H_(y){·} receives asinput the system output measurement, y_(meas), and outputs asubcomponent (ω_(y_meas)) of the ω tensor. Similarly, the filterrepresented by H_(K){·} receives as input a signal, y_(ζ)(k), whichcorresponds to a difference between the system output measurement,y_(meas) (or ω_(y_meas)), and the estimated system output, y_(est), andoutputs a subcomponent ω_(y_ud)) of the ω tensor. The estimated modelparameter tensor [θ] passed from the FELB 2304 also includes a pluralityof subcomponents (e.g., θ_(Ψ), θ_(K), θ_(Ω), θ_(Φ), θ_(ε)) that whencombined (e.g., tensor multiplied) with different subcomponents of the ωtensor allow different portions of the control signal, u_(SE), to beestimated. In other words, each mechanism/module/mapping operator in thesub engine 2305 that receives a subcomponent of the [θ] and [ω] tensorsgenerates a portion of the possible control signal (e.g., using controllaw 1A, where u_(SE)=θω).

FIG. 24 illustrates an example of an adaptive engine 2400, in accordancewith one or more implementations. As seen, the adaptive engine 2400comprises an estimation law module 2304 (also referred to as FELB 2304),an ATIMC sub engine 2305, and a selector module 2308. The sub engine2305 in FIG. 24 depicts some examples of the mapping modules, mappingoperators, filters, and mechanisms implemented within the ATIMC subengine, according to various aspects of the disclosure. FIGS. 25-30discuss these in further detail, but the purpose of the illustration inFIG. 24 is to show them at a higher level. The adaptive engine 2305comprises a plurality of mapping modules, including an Omega-Phi mappingmodule 2471, a Kappa-Aleph mapping module 2461, a Psi-Big Theta mappingmodule 2451, an Epsilon module 2441, a stabilization mechanism module2310, and a Kappa mechanism 2473. The adaptive engine 2305 furthercomprises a plurality of mapping operators, including an Omega mappingoperator 2472 (Ω{·}), a Psi mapping operator 2479 (Ψ{·}), and a Phimapping operator 2477 (Φ{·}). The adaptive engine 2305 also includes aplurality of filters, including filter 2474 (H_(K){·}), filter 2475(Hy{·}), filter 2476 (H_(ζ){·}), and filter 2478 (H_(Ω){·}). As seen,the estimation law module/FELB 2304 and the sub engine 2305 areconfigured to pass a plurality of signals between each other. For thesake of illustration, the dotted arrows represent subcomponents of the ωtensor that are passed from the different elements of the sub engine tothe estimation law module 2304, while the dash-dot arrows representsubcomponents (e.g., coefficients) of the estimated model parametertensor, [θ], that are produced by the estimation law module 2304 andpassed to the different elements of the sub engine 2305. In some cases,an element (e.g., mapping operator) of the sub engine may receive aportion (or subcomponent) of both the ω tensor and the estimated modelparameter tensor, [θ], and produce a portion (or subcomponent) of thepossible control signal, u_(SE). The various portions/subcomponents ofthe possible control signal may be combined to produce the possiblecontrol signal, u_(SE), passed to the selector module 2308, in someexamples.

Turning now to FIG. 25 , which illustrates a detailed view of a firstmapping module 2461 (i.e., the Kappa-to-Aleph mapping module, or simplyK-X mapping module 2461) of an adaptive engine 2500, in accordance withone or more implementations. In some examples, the K-X mapping module2461 serves as a noise and disturbance mapping module and helps generateone or more learned parameters (e.g., estimated parameters orcoefficients of the estimated model parameter tensor, θ) for mapping themeasured noise and disturbances (e.g., in the system output measurement,y_(meas)) to a control signal component. In other words, the K-X mappingmodule 2461 helps determine a control signal component of the possiblecontrol signal, u_(SE), or the control output signal, u_(out), that mayinduce/cause the noise and disturbances seen in the measurements. Due toits nature, its contemplated that the K-X mapping module 2461 may alsobe referred to as a noise-disturbance mapping module 2461.

As seen, the K-X mapping module 2461 comprises one or more Kappa mappingoperator 2585 (shown as K{·}), one or more Aleph mapping operators 2583(shown as X{·}), one or more delay blocks 2581, 2584 (shown asΔ_(KX){·}+I, Δ_(KX){·}), and a Big Theta operator 2586 (shown as Ξ{·}).FIG. 25 also depicts one or more mechanisms/operators/modules externalto the K-X mapping module 2461 (but within the sub engine 2305),including a filter 2587 (shown as H_(K){·}), a Psi mapping operator 2588(shown as Ψ{·}), a system output measurement filter 2569 (shown asHy{·}), and a Kappa mechanism 2473.

The K-X mapping module 2461 (i.e., the noise-disturbance mapping module2461) is configured to receive a subcomponent, ω_(y_nd), of the ωtensor, where the subcomponent, ω_(y_nd), corresponds to the portion ofthe system output (e.g., measured system output, y_(meas); estimatedsystem output, y_(est)) associated with noise and/or disturbance. Insome embodiments, this noise and disturbance portion of the systemoutput is isolated from the overall system output (e.g., y_(meas)) bysubtracting the mapped process output (i.e., generated by passing thecontrol output from the previous iteration, u_(out), through the Ψ{·}tensor mapping operator 2588) from the measured output (e.g., y_(meas)or ω_(y_meas)). In some cases, this noise/disturbance portion, y_(nd),of the system output is passed through the Kappa filter 2587 (H_(K){·}),which serves as the input filter to the Kappa Mechanism 2473 and the K-Xmapping module 2461. The filter 2587 outputs the signal, ω_(y_nd), andpasses it to the mapping module 2461.

In some cases, after the signal comprising the noise/disturbancesubcomponent, ω_(y_nd), is received at the K-X mapping module 2461, itis passed through each of the delay block 2581, the Aleph mappingoperator 2583, and the Kappa mapping operator 2585. The Kappa mappingoperator 2585 maps the noise/disturbance component, ω_(y_nd), of themeasured output to a corresponding noise/disturbance component,ω_(u_nd), of the control signal. In other words, ω_(u_nd) represents thepart of the control signal (e.g., control output signal, u_(out)) thatcorresponds to the additional noise and disturbance seen in the outputof the non-linear system being controlled. As seen, the Kappa operator2585 receives the coefficients (θ_(K)) of the model parameter tensor anduses them to map the noise/disturbance component, ω_(y_nd), of themeasured output to an approximation of the noise/disturbance component,ω_(u_nd_approx), of the control signal. This subcomponentω_(u_nd_approx)) of the ω tensor corresponding to an approximate of thenoise/disturbance inducing portion in the control signal (e.g., u_(SE)or u_(out)) is passed to the delay block 2584. The delay block 2584 alsoreceives a delay subcomponent, θ_(KXΔ), of the estimated model parametertensor, θ, where the delay subcomponent, θ_(KXΔ), defines the delayincrements/decrements to be applied to ω_(u_nd_approx). Applying ControlLaw 1A, where the control signal is a function of the estimated modelparameter tensor, θ, and the input regressor, ω, the output of the delayblock 2584 can be calculated to be a control signal,u_(nd_approx_delayed), which is a delayed version of the approximatednoise/disturbance component, ω_(u_nd_approx), of the control signal.

In some examples, the Big Theta operator 2586 (Ξ{·}) receives theapproximated noise/disturbance component in the control signal,ω_(u_nd_approx), from the Kappa operator 2585, a portion (θ_(Ξ)) of theestimated model parameter tensor, θ, from the estimation module 2304,and the control output from the previous iteration, u_(out), andproduces an approximate of the noise/disturbance component in themeasured system output, y_(nd_approx), and it to the Aleph operator2583.

The Aleph operator 2583 is used to produce an approximate of thenoise/disturbance component, u_(nd_approx), in the control signal thatcorresponds to the approximated noise/disturbances, y_(nd_approx), inthe output of the non-linear system. In some examples, the signalsu_(nd_approx) and u_(nd_approx_delayed) are passed to a summer, wherethe summer subtracts u_(nd_approx) from u_(nd_approx_delayed) to producean error signal (u_(nd_approx_error)) that is passed as one of the errorsignals to the estimation law module 2304. The estimation law module2304 also receives one or more other error signals, includingu_(nd_error), where u_(nd_error) is calculated from a difference betweenu_(nd)(k)−u_(nd_approx). The error signal, u_(nd_error), corresponds toan approximation/estimation error. In some cases, u_(nd_k) is producedat the output of the Aleph mapping operator 2583 based on mapping themeasured noise/disturbance component, y_(nd), to a corresponding controlsignal component, u_(nd), where the mapping is based on a portion(θ_(χ)) of the estimated model parameter tensor, θ. In some examples,the mapping comprises tensor multiplying the portion, θ_(χ), of theestimated model parameter tensor, θ, with the portion, ω_(y_nd)(k), ofthe ω tensor.

The delay block 2581 (Δ_(KX){·}+1) also receives the signal, ω_(y_nd_k),and outputs a delayed version of y_(nd_k). Here, the identitymatrix/tensor (i.e., ‘I’) is used to carry out the preparation of thecalculations for the next iteration. In other words, the delay block2581 is used to compute the value of the new delay increment/decrement(i.e., θ_(KXΔ)). Further, the output of the delay block 2581, which isy_(nd_k) (or ω_(y_nd_k)) delayed by the new delay increment/decrement,θ_(KXΔ), is passed to the Kappa mapping operator 2582. The Kappa mappingoperator 2582 also receives a subcomponent (θ_(K)) of the estimatedmodel parameter tensor, θ, which is used to map the y_(nd_k) delayed bythe new delay (i.e., y_(nd_k_delayed_new)) to a corresponding controlsignal component (approximate), u_(nd_approx_delayed_new). That is, theKappa mapping operator 2582 (on the left of the page) outputs a delayedversion of the approximated noise/disturbance component in the controlsignal, u_(nd_approx), where u_(nd_approx) is also delayed by the newdelay increment/decrement, as defined by θ_(KXΔ). For example, the Kappaoperator 2582 outputs the noise/disturbance portion of the controlsignal delayed by the new delay as u_(nd_approx_delayed_new) to theestimation law module 2304.

In some embodiments, the estimation law module 2304 thus receives aplurality of error signals (e.g., u_(nd_error), u_(nd_approx_error)) andan approximated noise/disturbance component, u_(nd_approx_delayed_new),from the K-X mapping module 2461 and outputs at least a portion (e.g.,one or more subcomponents) of the estimated model parameter tensor, θ.In this instance, the portions of the estimated model parameter tensor,θ, sent to the K-X mapping module 2461 comprise: one or more delays(e.g., B_(KXΔ)) and one or more coefficients (e.g., θ_(K), θ_(χ), θ_(Ξ),θ_(Ψ)) for the various tensorial mapping functions/operators (e.g., K{·}2582, X{·} 2583, Ξ{·} 2586, Ψ{·} 2588).

FIG. 26 illustrates a detailed view of the Epsilon mechanism module 2441of an adaptive engine 2600, in accordance with one or moreimplementations. The adaptive engine 2600 may be similar orsubstantially similar to the adaptive engines 2300-2500 described inrelation to FIGS. 23-25 . The adaptive engine 2600 comprises anestimation law module/FELB 2304, the Epsilon mechanism module 2441, andthe stabilization mechanism module 2310. As seen, the Epsilon mechanismmodule 2441 comprises a stability hypothesis tester 2691 configured toreceive a portion (e.g., one or more subcomponents or coefficients, suchas θ_(Ψ)) of the estimated model parameter tensor, θ, and output asubcomponent (e.g., θ_(u_des)) of the ω tensor to the estimation module2304. The Epsilon mechanism module 2441 (also referred to as aninstability prevention module 2441) is configured to “tensorially”generate stabilizing controllers, for instance, in the case that thelearned coefficient (θ_(Ψ) _(k) ) is unstable, which helps prevent thenon-linear system being controlled from going unstable. In other words,the Epsilon mechanism module 2441 helps prevent the learnedcoefficients, θ_(Ψ) _(k) , of the estimated model parameter tensor, θ,from going unstable. The module 2441 works in conjunction with thestabilization mechanism module 2310 to test a hypothesis, described infurther detail below.

As seen, the stabilization mechanism module 2310 is configured toreceive the θ_(ε) and θ_(Ψ) coefficients of the estimated modelparameter tensor, θ, from the estimation module 2304, and produce adesired and possible control signal, u_(des) or ω_(u) _(des) . Thisdesired and possible control signal, u_(des) or ω_(u) _(des) _(′) ispassed to the NL transfer functions 2313, which help compensate fora-priori known non-linear effects, and produces a possible controlsignal, u_(SE). In some examples, the desired and possible controlsignal, u_(des) or ω_(u) _(des) , is also passed to the stabilityhypothesis tester 2691 of the Epsilon mechanism module 2441. Thestability hypothesis tester 2691 also receives the θ_(W) coefficientsfrom the previous iteration (shown as θ_(Ψ_k−1)) and an input controlsignal component, ω_(u) _(in) , and determines if a predicted/estimatedsystem output (e.g., y_(est_SE)) is likely to go unstable. That is, theθ_(Ψ) coefficients are first used to map the input control signalcomponent, ω_(u) _(in) , to a predicted/estimated system output,following which the stability hypothesis tester 2691 determines if thepredicted/estimated system output will be stable or unstable. If thestability hypothesis tester 2791 determines that the predicted systemoutput will be unstable, the estimation law module/FELB 2304 is used toadaptively determine the θ_(ε) coefficients such that thepredicted/estimated system output will be stable. As shown in FIG. 26 ,these adapted θ_(ε) coefficients/parameters are passed to thestabilization mechanism 2310, where they may be used by a stabilizer(shown as stabilizer 3092 in FIG. 30 ) to stabilize the input controlsignal component, ω_(u) _(in) . In some embodiments, the stabilizationmechanism 2310 is configured to apply the stabilizer (not shown) if thepredicted system output from ω_(u) _(in) is going to be (or likely tobe) unstable. Thus, the possible control signal, u_(SE), produced byapplying the NL transfer functions 2313 to the control signal component,u_(des) or ω_(u) _(des) _(′) may be based on one of the original inputcontrol signal component, ω_(u) _(in) , or the input control signalcomponent after being passed through a stabilizer, ω_(u) _(in)_(_stabilized), further described below in relation to FIG. 30 .

FIG. 29 illustrates a block diagram showing the details of the Kappamechanism module 2473 of an adaptive engine 2900, in accordance with oneor more implementations. The adaptive engine may be similar orsubstantially similar to the adaptive engines 2300 and/or 2400previously described in relation to FIGS. 23 and 24 , respectively. TheKappa mechanism module 2473 in the ATIMC sub engine serves as a built-inmechanism to help prevent internal destabilization, for instance, if theadaptation has not converged yet. The H{·} filters (e.g., H_(K){·} 2587)of the ATIMC sub engine helps the adaptation achieve rapid convergenceby ensuring that persistent excitation signals have minimal to no impacton the measured system output, y_(meas). In other words, the Kappamechanism module 2473 may not be employed to reject disturbances untilthe adaptation has converged, in some examples. In this way, theestimated parameters/coefficients of the estimated model parametertensor, θ, have minimal to no change. After the adaptation hasconverged, the Kappa mechanism module 2473 is used to rejectnoise/disturbances (if any). Such a design facilitates in a stablecontrol output (i.e., a control output that prevents the non-linearsystem being controlled from going unstable). In some examples, theconvergence rate of the signals (e.g., persistent excitation signals)can be selected by the user/designer and input through a user interface.For example, the ATIMC sub engine allows the user to select theactuation rate and/or sensing rate, and the internal fundamental clockrate of the processor, to name two non-limiting examples. As usedherein, the term “actuation rate” refers to the control rate (or therate at which control signals are being generated). On the other hand,the term “sensing rate” refers to the rate at which the measurements arebeing taken/collected/obtained. In some cases, the actuation rate andthe sensing rate may be the same or different. Additionally, in somecircumstances, convergence can be reached within a fewcontrol/sensing/measurement samples. In some instances, convergence canbe reached in just a single control/measurement sample. Typically, theH{·} filters, such as, but not limited to, the H_(K){·} filter 2587, donot modify the measured/sensed samples at the time of measurement (e.g.,t_(k), t_(k+1) . . . t_(k+N)). Further, the control sampling rate(T_(s)) may be written as shown below:

$\begin{matrix}{T_{S} = {{t_{k + 1} - t_{k}} = \frac{t_{k + N} - t_{k}}{N}}} & \left( {{Equation}59} \right)\end{matrix}$

As noted above, the processor (e.g., FPGA processor, CPU processor) onwhich the adaptation calculations are executed is usually significantlyfaster than the control rate. In such cases, there may be multipleprocessor clock samples (e.g., FPGA and/or CPU clock samples) within asingle control sample. In one non-limiting example, there may be ten(10) processor clock samples for each control sample. That is,T_(p)=T_(s)/n=T_(s)/10, where T_(p) is the duration of one processorclock sample. In such cases, for each measurement/control sample, theremay be nine (9) iterations with a persistent excitation signal and one(1) with the actual control signal. It should be noted that, thisiteration factor (e.g., 9:1) may be considered a design variable and canvary depending on the u_(se) case. Additionally, or alternatively, theiteration factor may be selected based on determining an optimaliteration factor needed for a quick and/or robust convergence. In someexamples, the optimal iteration factor (e.g., 9:1, 12:1, 4:1, etc.) forthe number of persistent excitation signals for each control signal maybe determined empirically through experiments. In some cases, thepersistently exciting signal may be generated by adding noise, where thenoise comprises a spectral power covering the full operating range ofthe signals in question. That is, the additional noise generated isintended to cover the possible scenarios/situations that the nonlinearsystem is going to operate in, rather than creating a full noisespectrum. Such a design may enhance one or more of accuracy and speed ofnoise rejection, in some examples. In some cases, the spectral power ofthe additional noise may be determined based on the reference signal, r.The spectral characteristics of the added noise signals in question mayor may not be known a-priori. In some embodiments, an Additive WhiteGaussian Noise (AWGN) may be utilized if the spectral characteristics ofthe signals in question are not known a-priori. AWGN refers to a basicnoise model used in information theory and is used to mimic the effectof random processes occurring in nature. Other types of noise modelsknown and/or contemplated in the art may be utilized in differentembodiments, and the examples listed herein are not intended to belimiting.

As seen in FIG. 29 , the Kappa mechanism module 2473 (also referred toas the internal destabilization prevention module 2473) receives aninput tensor, [θ], where the input tensor, [θ], comprises at least thederivative of the estimated model parameter tensor, {dot over (θ)}. Insome cases, the input tensor [θ] also includes the estimated modelparameter tensor, θ. The Kappa mechanism module 2473 comprises aninfinity norm module 2961 configured to compute an infinity norm of theinput tensor (e.g., {dot over (θ)} tensor). The infinity norm module2961 passes the infinity norm to a comparison module 2962, whichcompares the infinity norm to a threshold. In one non-limiting example,the comparison module 2962 determines if the infinity norm is less thanor equal to the threshold. In some cases, the threshold may be specifiedby the user/designer and may be based in part on the precisioncapabilities (or precision characteristics) of the hardware and/or thesensing equipment, to name two non-limiting examples. In some othercases, the threshold may be based on a minimum Signal-to-Noise (SNR)requirement set by a customer or indicated in a product specification.As such, the threshold may correspond to the lowest value of noise thatmay be allowable based on the desired SNR. The Kappa mechanism module2473 also comprises a mapping operator 2585 (also referred to as Kappamapping operator 2585, or simply K{·} 2585) that is configured toreceive the 6K coefficients produced by the estimation law module 2304.The mapping operator 2585 also receives a noise/disturbance component ofthe measured signal, ω_(y_nd), which represents the effects of noiseand/or disturbance on the system output measurements, y_(meas). Themapping operator 2585 outputs a signal, u_(nd_true), which representsthe extra/added noise and disturbance rejection control component, tothe conditional block 2993. The conditional block 2993 also receivesanother signal, u_(nd_false), which represents zero (0) noise. Theconditional block 2993 takes the output (e.g., Boolean operator, such asTrue/False) from the comparison module 2962 and outputs a signal,u_(nd_out)=u_(nd_true), if the infinity norm is less than or equal tothe threshold, and outputs a signal, u_(nd_out)=_(und_false), if theinfinity norm is greater than the threshold. Said another way, the noiseand disturbance rejection control component, u_(nd_true), is added tothe possible control signal, u_(SE), or the control output, u_(out), ifthe adaptation has converged, in which case the “True” condition issatisfied. However, if the adaptation has not yet converged, the “False”condition is satisfied and u_(nd_false) (e.g., θ, or another valuespecified by the designer) is utilized, in which case no noise anddisturbance rejection may be carried out.

In some cases, the control signal component, u_(nd), corresponds to theportion of the control signal (e.g., u_(SE) or u_(out)) that induces thenoise/disturbance seen in the measured system output.

FIG. 27 illustrates a block diagram representation of the Psi-Big Thetamapping module 2451, in accordance with one or more implementations. Insome cases, the Psi-Big Theta mapping module 2451 is also referred to asthe control-to-measurement mapping module 2451, since it helps generatethe learned coefficients/parameters (e.g., one or more subcomponents ofthe estimated model parameter tensor, θ) to carry the mapping from thecontrol (e.g., possible control signal, u_(SE), control output, u_(out))to an estimated system output measurement, y_(est).

In some cases, the Big Theta operator 2586 (shown as Ξ{·}), is alsoreferred to as the sensitivity mapping operator 2586, and is used to mapa sensitivity in the Psi operator 2588 (Ψ{·}) to a change in input, suchthat:

${\Xi_{k}\overset{\Delta}{=}\frac{\nabla_{T}\Psi_{k}}{\nabla_{T}u_{k}}},$

where ∇_(T) is a tensorial gradient.

The Ξ operator 2586 is also employed to produce the coefficients, θ_(Ψ),that are fed to the Psi operator 2588 (Ψ{·}). In some aspects, the Ξoperator 2586 is used to determine the non-linear effects (if any)present around the Ψ operator 2588. Said another way, the use of the Ξoperator 2586 is similar to performing small signal analysis (e.g., inreal time) and the use of the Ψ operator 2588 is similar to performinglarge signal analysis. In some examples, the Ξ operator 2586 correspondsto a derivative or sensitivity function of the Ψ operator 2588. In suchcases, the Ξ operator 2586 and the Ψ operator 2588 may comprise, or maybe associated with, the same coefficients/parameters, but necessarilythe same dynamics. In this way, Ξ operator 2586 helps account for smallnonlinearities and the Ψ operator 2588 helps account for largernonlinearities in the process/parametric/nonlinear model behavior. Insome embodiments, obtaining the coefficients (θ_(Ξ)) of the modelparameter tensor, θ, may help determine the coefficients (θ_(Ψ)) of themodel parameter tensor, θ. Further, determining the coefficients, θ_(Ψ),helps ensure robustness and stability of the non-linear system beingcontrolled, as small changes can often amplify and induce large(undesirable) effects in non-linear systems. As noted above, thecoefficients, θ_(Ψ), passed to the Psi operator (e.g., Psi operator2479, 2588) may be used to map a control signal (e.g., u_(out)) to anestimated system output (e.g., y_(est)). Thus, accurate determination ofthe coefficients, θ_(Ψ), facilitates in reducing or minimizing theestimation error (e.g., error corresponding to a difference between anestimated system output, y_(est), and a measured system output,y_(meas)). In some cases, the coefficients θ_(Ψ) and θ_(Ξ) of theestimated model parameter tensor, θ, sent to the Ψ operator 2588 and theΞ operator 2586, respectively, may be the same or substantially thesame. In other words, θ_(Ψ)=θ_(Ξ), in some examples. However, it shouldbe noted that Ψ{·} may or may not be equal to Ξ{·}.

In some examples, the Psi mapping function/operator 2479 (Ψ{·}), whichis an example of a tensorial identity mapping operator, is employed tomap a control signal (e.g., control output from a previous iteration,u_(out_k−1); possible control signal, u_(SE)) to an estimated systemoutput measurement, y_(est). It should be noted that the estimatedsystem output measurement produced by the Ψ mapping operator 2479 may bebased on the control signal that is input to the mapping operator 2479.For example, if the Ψ mapping operator 2479 receives a control outputfrom a previous iteration, u_(out_k−1), it produces a total estimatedsystem output, y_(est_out). If the Ψ mapping operator 2479 receives apossible control signal, u_(SE), for the ATIMC sub engine, it outputs apossible estimated system output, y_(est_SE), corresponding to the ATIMCsub engine. Thus, as seen, the estimated system output measurementproduced by the Ψ mapping operator 2479 is based on the control input(u_(out) in this example) and a subcomponent (e.g., θ_(Ψ) coefficients)of the estimated model parameter tensor, Θ.

As seen in FIG. 28 , the total estimated system output, y_(est_out),produced by the Ψ mapping operator 2479 is passed to a summer, where itis subtracted from the system output measurement, y_(meas), to producey_(ζ(k)), where y_(ζ(k)) represents the effects of ω_(uζ) on the output.In some examples, ω_(uζ) represents a noise signal added to the controlto enhance accuracy and/or convergence of the adaptation. In someexamples, the added noise signal, ω_(uζ), is within the specificationand/or tolerances specified by the end-user or designer. The noisesignal, ω_(uζ), may be determined by mapping the specifications andtolerances, ζ_(spec), specified by the user to a corresponding controltensor component given by ω_(uζ). As shown in FIG. 23 , this mappingfrom the user specified specifications/tolerances, ζ_(spec), to thenoise signal, ω_(uζ), is carried out by the mapping operator 2314(Φ{·}). Thus, the mapping operator 2314 is configured to map a variationor sensitivity in the system measurement outputs, y_(meas), to anadditive control component. Generation of this additive noise signal (ortensor control component), ω_(uζ), helps the ATIMC sub engine convergeto the process model in real-time (or substantially real-time) as itreduces the time needed for identification of the non-linearities (e.g.,small nonlinearities or chaotic behavior). From a practical standpoint,this means that the mapping operator 2314 (Φ{·}) helps assess how theuser specified tolerance affects the control (e.g., possible controlsignal, u_(SE), control output, u_(out), or another applicable controlsignal). It should be noted that, the additive noise signal used toidentify the small nonlinearities/chaotic behavior are within the userspecified tolerance (i.e., to ensure that the measured system output,y_(meas), matches or substantially matches the one desired by the user).In some aspects, this allows determination of the small nonlinearities(i.e., via the added noise), while at the same time having minimal to noeffect on the system output, y_(meas), as seen by the user. In this way,the possible control signal, u_(SE), output by the ATIMC sub enginefacilitates responsiveness (e.g., maximize dynamic range in real time)and adaptability of a parallel multi-actuator nonlinear and/or chaoticcontrol system. Moreover, such a design facilitates in improved controls(e.g., to maximize the speed of the response and achieve the shortestresponse time to reach a desired reference signal value, while alsoenabling stability and robustness) of a parallel multi-actuatornonlinear and/or chaotic control system. In some cases, the delayestimation and predictive aspects and adaptation aspects of the ATIMCsub engine may also enable all of the above functions and advantages tobe achieved even when some of the actuators of the control system arearbitrarily slower than other actuators of the control system.

Returning now to FIG. 27 , where the noise signal (ω_(uζ)) is added toan “ideal” control signal component, ω_(u_ideal_k). Specifically, thenoise signal (ω_(uζ)) and the control signal (ω_(u_ideal_k)) are inputto the mapping operator 2586 which outputs an estimate y_(est_ζ), wherethe estimate, y_(est_ζ), represents the effects of the noise signalω_(uζ) on the possible estimated system output, y_(est_SE). In someaspects, the estimate, y_(est_ζ), is similar to the estimate, y_(ζ(k)),in that it represents the effects of the noise signal (ω_(uζ)) on thesystem output. The difference being that y_(est_ζ) represents theeffects of the noise signal on the possible estimated system output,y_(est), while y_(ζ(k)) represents the effect of the noise signal on themeasured system output, y_(meas). In some cases, the estimates y_(est_ζ)and y_(ζ(k)) are passed to a summer, which outputs y_(ζ_error) based onsubtracting y_(est_ζ) from y_(ζ(k)). As described above, the estimationlaw module/FELB 2304 is configured to receive one or more error tensorsand output one or more estimated model parameter tensors, θ. As seen inFIG. 27 , the estimation/approximation error signal, y_(ζ≤error), ispassed to the estimation law module 2304. Further, the estimation lawmodule 2304 processes the approximation/estimation error signal,y_(ζ_error), corresponding to the effects of the noise signal andattempts to find the coefficients (θ_(Ξ)) of the estimated modelparameter tensor, θ, that minimize this error. That is, the estimationlaw module 2304 produces the coefficients, θ_(Ξ), with the goal ofmaking the error, y_(ζ_error), equal to zero. Once the estimation lawmodule 2304 produces the coefficients, θ_(Ξ), it passes them to theATIMC sub engine 2305 where they are input to the mapping operator 2586.The estimation law module 2304 also produces the coefficients, θ_(Ψ),and passes them to the sub engine 2305 where they are input to themapping operator 2479. In some cases, the coefficients θ_(Ψ) passed tothe mapping operator 2479 are equal to the coefficients θ_(Ξ) passed tothe mapping operator 2586.

In some embodiments, the control signal, θ_(u_ideal_k), may be generatedfrom the output of the Omega operator 2472 (Ω{·}) shown in FIG. 28 .Specifically, ω_(u_nd), which is the portion of the control signal thatcorresponds to the additional noise and disturbances seen at the outputof the non-linear system is subtracted from the output, u_(r_des)(k), ofthe Omega operator 2472 to produce the control tensor component,ω_(u_ideal_k). The control tensor component, ω_(u_ideal_k), thuscorresponds to an “ideal” control signal component (or control tensor)as the noise and/or disturbances in the non-linear system beingcontrolled have been compensated for. In some examples, the controltensor component, ω_(u_ideal_k), is added to the noise signal, ω_(uζ),to produce a control tensor component, ω_(u_in), that is input to thestabilization mechanism module 2310 (as shown in FIG. 26 ). Thestabilization mechanism module 2310 uses the input control tensorcomponent, ω_(u_in), to produce a control tensor component, ω_(u_des),which is passed to the NL transfer functions 2313 (also referred to asNL compensator 2313). The NL transfer functions 2313 produce thepossible control signal, u_(SE), from the control tensor component,ω_(u_des). As seen in FIG. 23 , the NL transfer functions 2313 pass thepossible control signal, u_(SE), to the selector module 2308.

As shown in FIG. 27 , the noise signal, ω_(uζ), and the control signal,ω_(u_ideal_k), are passed to the tensorial mapping operator 2586 (Ξ{·}),where the tensorial mapping operator 2586 also receives the θ_(Ξ)coefficients of the estimated model parameter tensor, θ, from theestimation law module 2304. The tensorial mapping operator 2586 outputs,y_(est_ζ), to a summer, where y_(est_ζ) represents the effects of thenoise signal ω_(uζ) on the possible estimated system output, y_(est_SE).In some examples, the adaptation (e.g., adaptively generating thecoefficients, θ_(Ψ), θ_(Ξ) to minimize the error, y_(ζ_error)) in FIG.27 works based on the difference between the measurements, y_(meas), andthe approximated/estimated system output from the control signal,ω_(u_ideal_k).

Omega-Phi Mapping Module of the ATIMC Sub Engine

The Omega-Phi Mapping Module (e.g., shown in FIG. 28 ) is configured to“tensorially” generate the learned parameters/coefficients for carryingout the mapping from the desired setpoint (ω_(r_des)) to a desiredcontrol signal (ω_(u_des)). That is, the Omega-Phi Mapping Module 2471described in relation to FIG. 28 helps produce the possible controlsignal, where the possible control signal is based at least in part onadaptively determining the coefficients (θ_(Ω)) of the estimated modelparameter tensor, θ. In some examples, the Omega-Phi mapping module 2471is also referred to as the reference-to-possible control mapping module2471.

In some embodiments, the Omega operator/mechanism/module 2472 (shown asΩ{·}) serves as the control law portion of the ATIMC sub engine as itproduces the desired control signal, ω_(r_des)(k), where the desiredcontrol signal is based at least in part on the desired setpoint (i.e.,reference signal, r).

As shown in FIG. 28 , the Omega-Phi mapping module 2471 receives adesired setpoint, (ω_(r_des)), where the desired setpoint is passed to adelay block 2891 (Δ_(ϕΩ){·}), a stable zero dynamics hypothesis tester2892, and a mapping operator 2472 (Ω{·}). The delay block 2891 is alsoconfigured to receive a delay portion/subcomponent (θ_(ϕΩΔ)) of theestimated model parameter tensor, θ, from the estimation law module2304. In some examples, the delay subcomponent (θ_(ϕΩΔ)) defines a delayincrement/decrement that is applied by the delay block 2891 to thedesired setpoint, ω_(r_des). The delay block 2891 then outputs a delayedversion of the desired setpoint, ω_(r_des_delayed_new), with the newdelay (e.g., defined by the delay subcomponent, θ_(ϕΩΔ)) received fromthe estimation law module 2304. In some examples, the delayed version ofthe desired setpoint, ω_(r_des_delayed_new), is passed to the Omegamapping operator 2472. The omega mapping module 2472 (on the left of thepage) also receives the coefficients (θ_(Ω)) of the estimated modelparameter tensor, θ, and passes a tensor, ω_(ϕΔ), to the estimation lawmodule 2304, where the tensor, ω_(ϕΔ), corresponds to a delay.Specifically, the estimation law module uses ω_(ϕΔ) to generate thedelay subcomponent (θ_(ϕΩΔ)) that is passed to the delay block 2891.

Moving on to the stable zero dynamics hypothesis tester 2892 (alsoreferred to as tester 2892), which is also configured to receive thedesired setpoint, ω_(r_des). The tester 2892 receives the desiredsetpoint, ω_(r_des), processes it, and outputs the desired setpoint,ω_(r_des), along with a True/False hypothesis. In some cases, the tester2892 is configured to test whether the desired setpoint, ω_(r_des), hasstable or unstable zero dynamics and pass a True/False hypothesis to thedelay block 2891 (Δ_(ϕΩ){·}). The delay block 2891 applies the delayincrement/decrement defined by the delay component, Δ_(ϕΩ), to thedesired setpoint, ω_(r_des), and passes the desired setpoint with thedelay, ω_(r_des)_delayed, to the Phi mapping operator 2477 (Φ{·}).

The Phi mapping operator 2477 maps the desired setpoint (with thedelay), (ω_(r_des_delayed), to a corresponding control signal value,u_(r_des_direct), and passes this control signal value to a summer. Insome examples, the summer also receives another control signal value,u_(r_des_approx), which is subtracted from the control signal value,u_(r_des_direct), to produce an error signal,u_(r_des_error_zero_dyn_stab), that is then passed to the estimation lawmodule. This error signal, u_(r_des_error_zero_dyn_stab), corresponds toa difference between an approximated control output, u_(r_des_approx),and the estimated control output, u_(r_des_direct), had the systemoutput measurement, y_(meas), been equal to the desired setpoint, asfurther described below.

The goal of the Omega-Phi mapping module 2471 is to find thecoefficients (θ_(Ω)) of the estimated model parameter tensor, θ, thatcorrespond to the minimum error between the approximated control output,u_(r_des_approx), and the estimated control output, u_(r_des_direct),had the system output measurement, y_(meas), been equal to the desiredsetpoint (ω_(r_des)). Thus, by minimizing the difference (or error)given by u_(r_des_direct)−u_(r_des_approx), the adaptive engine canconverge to the coefficients (θ_(Ω)) of the estimated model parametertensor, θ, from which the possible control signal, u_(SE), can bedetermined. In some examples, the estimated control output,u_(r_des_direct), can be obtained by mapping an undisturbed and/ornoiseless reference signal (or setpoint) to its corresponding controlvalue. In some cases, this mapping can be achieved through the Phimapping operator 2477. The estimation law module 2304 is configured toadaptively find and pass the coefficients θ_(Φ) of the estimated modelparameter tensor, θ, to the Phi mapping operator 2477, where thecoefficients θ_(Φ) are determined in real-time by minimizing the error(e.g., for the current iteration ‘k’) between u_(r_des_direct) andu_(r_des_approx) In some examples, the control signal value,u_(r_des_approx), is produced by mapping (using the mapping operator2477), y_(r_des), to a control signal value. Specifically, the desiredsetpoint (ω_(r_des)) is mapped to a desired control signal value(u_(r_des)) using the Omega mapping operator 2472 and the coefficientsθ_(Ω). Next, the desired control signal value (u_(r_des)) is mapped to adesired system output (y_(r_des)) using the Psi operator 2479 and thecoefficients θ_(Ψ), where the Psi operator 2479 is similar orsubstantially similar to the mapping operator 2479 described in relationto FIG. 27. For example, the mapping operator 2479 is configured to mapa control signal value (u) to a system output (y), where the mapping isbased at least in part on the coefficients (θ_(Ψ)) received from theestimation law module 2304. Further, the Phi mapping operator 2477receives the coefficients (θ_(Φ)) from the estimation law module 2304and maps the undisturbed and noiseless measurement (y_(r_des)) to acorresponding control signal value (u_(r_des_approx)). In some examples,this approximated control signal value (u_(r_des_approx)) is passed to asummer, where it is subtracted from the delayed control signal value(u_(r_des_delayed)) to produce an error signal (u_(r_des_error)), wherethe error signal (u_(r_des_error)) is passed to the estimation lawmodule 2304 in the error tensor ‘e’ described above.

In some cases, the estimation law module 2304 receives the one or moreerror signals (e.g., u_(r_des_error), u_(r_des_error_zero_dyn_stab),ω_(ΦΔ)) from the Omega-Phi mapping module 2471 and uses them todetermine the delay increments/decrements (e.g., θ_(ϕΩΔ)) and/or thecoefficients (e.g., θ_(Φ), θ_(Ω), θ_(Ψ)) of the estimated modelparameter tensor, θ.

The estimated model parameter tensor, θ, includes θ_(Ω)coefficients/parameters that are determined through adaptation. Further,the Omega operator 2472 (Ω{·}) is a tensorial mapping function/operatorthat is employed to map a desired reference signal/setpoint (e.g.,ω_(r_des)) to a corresponding control signal value, e.g., u_(r_des). Insome examples, the Omega operator 2472 may be configurable by theend-user or designer and may comprise linear and/or non-linearfunctions/operators. In one non-limiting example, the Omega operator2472 (Ω{·}) may be implemented by way of an Artificial Neural Network(ANN). In some other cases, the Omega operator 2472 may comprise a gaintensor whose weights/parameters are set using the θ_(Ω) coefficients,where the θ_(Ω) coefficients are adapted in real-time (or substantiallyreal time).

In some examples, the adaptive engine comprising the estimation lawmodule 2304 and the ATIMC sub engine 2305 uses adaptation to determinethe total estimated delay (Δ_(Total)). After initializing the totalestimated delay (Δ_(Total)), the different mapping mechanisms/modules ofthe ATIMC sub engine 2305 adapt the delay to further enhance theperformance of the adaptive engine (e.g., to bypass unstable zerodynamics if they are present in the non-linear system). The use of“delayed” and “undelayed” versions of various signals helps preventdivergence of the control/adaptation against unstable zero dynamics. Insome aspects, the extra delay allows the controller to be conscious ofthe unstable zero dynamics. An example for unstable zero dynamics may bethat a system takes time to charge/build up. In such cases, the additionof the delay helps prevent the controller from increasing the value ofthe control signal, u_(out), applied to an actuator (e.g., if it assumesthat the control signal value that it is issuing is not enough). Inother words, the addition of the delay helps account for the fact thatthe non-linear system being controlled may need time (e.g., due tounstable zero dynamics) to respond to such a control output, u_(out).Thus, the delays described herein assist in the control of non-linearsystems having unstable zero dynamics. In some cases, the system of thepresent disclosure is configured to determine a total delay (Δ_(Total)).The ATIMC sub engine comprises a plurality of mechanism mapping modules,each associated with a slightly different delay. In some cases, thedifferent delays (e.g., θ_(ϕΩΔ), θ_(KXΔ), etc.) passed from theestimation law module 2304 may be added to the total delay (Δ_(Total))to produce the delay (e.g., θ_(ϕΩΔ), Δ_(KX)) for the different mappingmodules. The delays passed from the estimation law module/FELB 2304 maycomprise positive or negative integer values, and each additional delayincrement/decrement may correspond to one control sample. Such a designfacilitates in optimizing the time needed to achieve convergence in thecase of unstable zero dynamics. Furthermore, when the non-linear systembeing controlled has no unstable zero dynamics (i.e., has stable zerodynamics), the adaptive engine 2300, 2400 comprising the estimation lawmodule/FELB 2304 and the ATIMC sub engine 2305 may not add any delays,which also optimizes the time needed to achieve convergence.

FIG. 30 shows a detailed view of the stabilization mechanism module 2310of the ATIMC sub engine, in accordance with one or more implementations.The stabilization mechanism module 2310 may be similar or substantiallysimilar to the stabilization mechanism module 2310 previous described inrelation to FIG. 26 . The stabilization mechanism module 2310 helpsensure (adaptively) that the process/non-linear system being controlledremains stable, regardless of operating conditions. As seen, thestabilization mechanism module 2310 comprises a stability hypothesistester 3091. The stability hypothesis tester 3091 implements one or moreaspects of the stability hypothesis tester 2791 described above inrelation to FIG. 26 . The stabilization mechanism module 2310 alsoincludes an optional stabilizer 3092. In some embodiments, thestabilizer 3092 is deployed if the predicted system output measurementfor a possible control signal (e.g., determined based on applying thepossible control signal to one or more of the estimation laws describedthroughout the disclosure) is going to be unstable.

As seen, the estimation law module/FELB 2304 is configured to produceone or more estimated parameter tensors, θ, where the one or moreestimated parameter tensors comprise one or more subcomponents (alsoreferred to as coefficients), such as, θ_(Ψ), θ_(ε), etc. In the exampleshown, the stability hypothesis tester 3091 is configured to receive thecoefficients, θ_(Ψ) and θ_(ε), of the estimated model parameter tensor,θ, and output a Boolean response (e.g., True/False) based on predictingif the system output will be unstable. In some cases, the stabilizationmechanism module 2310 also receives as input the control tensorcomponent, ω_(u_in), where the control tensor component, ω_(u_in), isgenerated by adding ω_(u_ideal_k) to the noise signal, ω_(uζ), asdescribed above. Next, the stability hypothesis tester 3091 uses one ormore of the control tensor component, ω_(u_in), the θ_(Ψ), and the θ_(ε)parameters/coefficients to predict the stability of the system output.If the predicted system outputs are stable, the stability hypothesistester 3091 outputs “True” to the conditional block 3093, in which casethe conditional block 3093 passes the control tensor component,ω_(u_in), as the desired control output, ω_(u_des), to one or more ofthe Epsilon mechanism module 2441 and the NL transfer function 2313. Insome other cases, if the predicted system outputs are unstable, thestability hypothesis tester outputs “False” to the conditional block3093. In such cases, the optional stabilizer 3092 is used to stabilizethe control tensor component, ω_(u_in). In some examples, the stabilizer3092 outputs another control tensor component, ω_(u_in_stabilized), tothe conditional block 3093, which then outputs the stabilized controltensor component, ω_(u_in_stabilized), as the desired control output,ω_(u_des). In some examples, the desired control output, ω_(u_des), isalso passed back to the estimation law module/FELB 2304. The estimationlaw module 2304 adapts the θ_(ε) parameters/coefficients, for instance,if the desired control output, ω_(u_des), is different from the controltensor component, ω_(u_in), if the stabilizer 3092 was deployed, or acombination thereof. In other words, the θ_(E) parameters/coefficientsmay be adapted (i.e., adaptively determined) such that the predictedsystem output measurement(s) are stable.

FIG. 22 illustrates an example of a method 2200 for controlling anon-linear system using an ATIMC control law module/sub-engine, inaccordance with one or more implementations. The operations of method2200 presented below are intended to be illustrative. In someimplementations, method 2200 may be accomplished with one or moreadditional operations not described, and/or without one or more of theoperations discussed. Additionally, the order in which the operations ofmethod 2200 are illustrated in FIG. 22 and described below is notintended to be limiting.

In some implementations, method 2200 may be implemented in one or moreprocessing devices (e.g., a central processing unit or CPU, a digitalprocessor, an analog processor, a digital circuit designed to processinformation, an analog circuit designed to process information, a statemachine, a field programmable gate array or FPGA, and/or othermechanisms for electronically processing information). The one or moreprocessing devices may include one or more devices executing some or allof the operations of method 2200 in response to instructions storedelectronically on an electronic storage medium. The one or moreprocessing devices may include one or more devices configured throughhardware, firmware, and/or software to be specifically designed forexecution of one or more of the operations of method 2200.

As seen, a first operation (2202) comprises receiving a referencesignal, r, where the reference signal, r, may be received at theestimation law module/FELB 2304. A second operation 2204 comprisesreceiving at least one system output measurement, y_(meas). In someembodiments, the system output measurement, y_(meas), is received at theestimation law module/FELB 2304. A third operation (2206) comprisesdetermining one or more of an estimation law and/or control law forselecting controller coefficients (also referred to as estimatedparameter tensor coefficients or estimated model parameter tensorcoefficients, such as the coefficients, θ_(Ω)), where the controllercoefficients are predicted to minimize or reduce at least one errorindex (e.g., corresponding to the various errors passed from the controllaw module/sub-engine 2305 to the estimation law module 2304). A fourthoperation (2208) comprising generating a control signal, u_(c) (e.g.,ω_(u_ideal_k) in FIG. 27 ) based at least in part on determining thecontrol law portion for selecting the controller coefficients. A fifthoperation (2210) comprises generating a possible control signal, u_(SE),for the current iteration after removing the effects of noise and/ordisturbance (e.g., u_(nd), or u_(nd_approx)) from the control signal,u_(c). Specifically, the possible control signal, u_(SE), may begenerated as: u_(SE)=u_(c)−u_(nd).

In some cases, sixth operation (2212) comprises determining an idealprocess output, y_(p). More specifically, the adaptive engine (e.g.,adaptive engine 2300) determines an ideal process output, y_(p), byapplying the possible control signal, u_(SE), to the non-linear model(e.g., the estimation portion of the non-linear model).

As described above in relation to FIG. 25 , the control output, u_(out),may be passed through the mapping operator 2588 to produce the totalestimated system output, y_(est_SE) or y_(est_out). Additionally, thenoise/disturbance component (e.g., ω_(y_nd)(k) or y_(nd)) in themeasured system output, y_(meas), may be calculated from a differencebetween the ideal system/process output (e.g., y_(est_SE) ory_(est_out)) and the measurement, y_(meas). Similarly, at operation(2214), the method 2200 comprises estimating (or determining) theeffects of noise and disturbance, y_(nd), in the measured system output,y_(meas). In some examples, the estimation of the noise/disturbanceeffects, y_(nd), comprises evaluating a difference between the measuredsystem output, y_(meas), and the ideal system/process output, y_(p). Insome cases, the ideal system/process output, y_(p), discussed inrelation to FIG. 22 may be similar or substantially similar to the totalestimated system output (e.g., y_(est_SE) or y_(est_out)) described inother portions of this disclosure.

An eighth operation (2216) comprises determining, u_(nd), where u_(nd)corresponds to the portion of the control signal (e.g., possible controlsignal, u_(SE); control output from the previous iteration, u_(out_k−1))associated with the noise and/or disturbance effects. In some cases,determining the noise/disturbance inducing portion of the controlsignal, u_(nd), comprises mapping the measured noise and disturbancecomponent, y_(nd), to a corresponding control signal value, as describedabove in relation to FIG. 25 . In some cases, the estimated/approximatedu_(nd) (i.e., determined at operation 2216) is used to generate thecontrol signal output for the next iteration. Furthermore, the adaptiveengine is configured to update/adapt the estimated parameter.

Although not illustrated, the ATIMC sub-engine can operate as astandalone controller. In such an embodiment, the estimation lawmodules/FELB can be replaced by an empirically derived lookup table forthe estimated model parameter tensors, Θ. More specifically, a lookuptable can be empirically formed as a mapping between (1) y_(meas) andu_(out) from a reference/calibration system and (2) estimated modelparameter tensors, Θ. During operation of the ATIMC standalonecontroller as a standalone controller, a control, u_(out), can beprovided to the one or more actuators, and measurements, y_(meas), canbe taken from the one or more actuators and/or system. These can then beused to select estimated model parameter tensors, Θ, from the lookuptable, and then provided to the ATIMC standalone controller to determinewhat will be called a control signal, u_(out). This control signal,u_(out), can be provided to the one or more actuators. Alternatively,the ATIMC standalone controller can produce a string of possible controlsignals, u_(se), and form a control, u_(out), as a combination of thestring. For instance, a weighted average of the possible controlsignals, u_(se), can be used to calculate the control, u_(out), althoughother methods of combining the string can also be implemented. In someembodiments, the combination may be based on estimated system outputs,y_(est_se), for each of the possible control signals, u_(se), similar tothe way in which a topology is selected in the selector and combinermentioned earlier. These estimated system outputs, y_(est_se), can befound via an estimation portion of the nonlinear model, for instance,using Model 1:

y _(est_se) =W _(m) {u _(se),Θ}

Where the estimated model parameter tensor, Θ, is found in the lookuptable based on the measured system output, y_(meas), and the control,u_(out), both from a previous iteration.

The ATFC Controller and Control Law Module or Sub-Engine

Referring next to FIG. 31 , shown is a block diagram of an adaptivetensorial fuzzy controller (ATFC) 3100 that may be implemented as astand-alone control law module 506 or it may be implemented among othercontrol law modules 506 in the adaptive engine 500 described withreference to FIGS. 5A, 5B, and 5C. As shown, the ATFC 3100 comprises afuzzy controller 3102 that includes a fuzzification module 3104, that iscoupled to an inference mechanism 3106, and the inference mechanism 3106is coupled to a defuzzification module 3108 and a rule base 3110. Alsoshown is a dynamic modification module 3112 that is coupled to thefuzzification module 3104, the rule base 3110, and the defuzzificationmodule 3108. It should be recognized that the depiction of thecomponents that make up the ATFC 3100 is a logical depiction offunctional blocks, and each functional block may be combined with otherfunctions or further separated in an actual implementation. For example,the fuzzification module 3104 may be separated into a fuzzy input scalermodule and a fuzzifier module and the defuzzification module may beseparated into a defuzzifier module and a fuzzy output scaler module asshown in FIG. 39 . As discussed further herein, the depicted functionalblocks may be realized by memory, processor executable instructionsstored in memory, and a field programmable gate array programmed withinstructions stored in memory.

In operation, the fuzzification module 3104 generally operates totransform input variables into fuzzy values that are in a form that theinference mechanism 3106 can handle utilizing input membership functions(MFin). The inference mechanism 3106 then generates a fuzzy output 3114according the rule base 3110, and the defuzzification module 3108transforms, utilizing output membership functions (MFout), the fuzzyoutput 3114 into a possible control signal, use, that is either used forcontrolling one or more actuators 408 of the plasma processing system(if the ATFC 3100 is utilized as a stand-alone control law module 506)or the possible control signal, u_(se), is provided to the selectormodule (if the ATFC 3100 is utilized in connection with other controllaw modules 506) as described with reference to FIGS. 5A, 5B, and 5C.

In general, the dynamic modification module 3112 is configured to adaptinput membership functions, MFin, of the fuzzification module 3104,output membership functions, MFout, of the defuzzification module 3108,and the rule base 3110 while controlling an output (e.g., the loadoutput 430) of a plasma processing system (e.g., plasma processingsystem 400). Aspects and variations of the dynamic modification module3112 are discussed further herein.

While referring to FIG. 31 , simultaneous reference is made to FIG. 32 ,which is a flowchart depicting a method for controlling a plasmaprocessing system such as the plasma processing systems 100, 400described with reference to FIGS. 1 and 4 . At the outset, it isimportant to note that the method depicted in FIG. 32 is applicable inthe context of tensorial control where there are potentially multipleoutputs, multiple controller parameters, and multiple actuators that areutilized to achieve desired parameter values, but FIG. 32 is simplifiedfor purposes of clarity.

As shown, the method includes receiving a reference signal, r, (e.g.,reference signal 405) defining target values for a parameter that iscontrolled at an output (e.g., at the load output 430) of the plasmaprocessing system (Block 3202). The controlled parameter may be, forexample, forward power and the target values may, for example, definestates of a multilevel power setpoint (e.g., as shown in FIG. 2 ). Themethod also comprises obtaining a measure, y_(meas), of the parameterthat is controlled at the output (Block 3204). At least one sensor(e.g., sensor(s) 410) including, for example and without limitation,directional couplers, VI sensors, current transducers, and simplevoltage sensors may be used to obtain the measure, y_(meas), of theparameter that is controlled at the output. Again, it should be notedthat there may be multiple controlled parameters (such as forward power,voltage, current, substrate bias voltage, ion energy, frequency,impedance, etc,) and there may be multiple outputs (e.g., one or more ofthe load output 430 and/or the actuator outputs 432). Those of ordinaryskill in the art will appreciate that the signals from the at least onesensor may be sampled and converted into digital format for use by theadaptive engine 420.

As shown, the method also includes producing an estimated modelparameter tensor, Θ (Block 3206). As previously discussed with referenceto FIGS. 5A, 5B, and 5C an estimation law module 504 may take as inputregressor, Ø, or a subset thereof, including values such as thereference signal, r, and the measured system output, y_(meas), and anestimated error, ê, and the estimation law module 504 may process theseinputs through an estimation law to produce the estimated modelparameter tensor, Θ.

As shown, the fuzzy controller 3102 provides a control signal to adjustat least one actuator based at least upon the reference signal and themeasure of the controlled parameter (Block 3208). As discussed above, inthe context of an adaptive engine 500 that includes multiple control lawmodules 506, the control signal may be a possible control signal,u_(se). Or the ATFC A00 may operate as a standalone control law moduleto provide control, u_(out), as a signal that is used to control anactuator 408.

In addition, the dynamic modification module 3112 adapts the outputmembership functions (MFout) of the fuzzy controller 3102, inputmembership functions (MFin) of the fuzzy controller 3102, and a rulebase 3110 of the fuzzy controller 3102 while controlling the output ofthe system, based at least upon the estimated model parameter tensor, Θ,the reference signal, r, the estimate of the controlled parameter,y_(est_se), the measure of the controlled parameter, y_(meas), and thecontrol signal (u_(se) or u_(out))(Block 3210). The output membershipfunctions, the input membership function and the rule base may beadapted simultaneously during each sample or the output membershipfunctions, the input membership function and the rule base may beadapted asynchronously.

Beneficially, the ATFC 3100 is able to extend the regions of operationof the plasma processing system 100, 400 that is driving a nonlinearand/or chaotic load 104 where (in some embodiments) aspects of thesystem 100, 400 can still be controlled at a nanosecond scale at auser's specific specifications.

More specifically, aspects of the ATFC 3100 enable the addition ofheuristic, rule-based, case-by-case knowledge to the control mechanismthat other control methodologies cannot achieve. In addition, theadaptive aspects of this mechanism enable updating and changing theserules and/or the addition of rules that cover more regions while thesystem is running so performance and stability are maintained, and if anew process (e.g., for processing a work piece) is added, the rules maybe extended to that process.

Standard fuzzy technology suffers from not being able to be implementedto its full extent into real time devices that deal with highlyuncertain and nonlinear/chaotic systems. In contrast, embodiments of theATFC 3100 overcome memory limitations by using tensor signal processingand storage. In addition, by using rule estimation (executed, e.g., byan estimation law module 504), the rule base 3110 of the fuzzycontroller 3102 may be dynamically adjusted at every control sample, Ts,to deal with systems and/or operating conditions that a designer did notconsider during the design stage. This dynamic adjustment provides atremendous advantage over linear adaptation and/or robust controlmethodologies that need knowledge of the dynamics of the process andquantization of uncertainties which cannot be known a-priori in highlynonlinear/uncertain systems to perform well.

Other “non-fuzzy” control systems (e.g., robust learning controlsystems) may be superior when the system is operating within predefined,a-priori contemplated, regions because accurate a-priori knowledge isvery useful but operating in accurately known a-priori-defined regionsis more of an exception rather than the general case. As a consequence,using both robust learning control and adaptive tensorial fuzzy controlextends performance, reliability, stability and the operating regions ina complimentary non overlapping way; thus, producing a superior product(e.g., processed workpiece) with very little added costs.

Portions of the ATFC 3100 mechanism may be implemented in real timehardware as discussed further below (e.g., by using TSP RAM, registers,and general tensor signal processing). It should be noted that althoughsome of the terminology used to characterize the ATFC 3100 is similar toterminology used in connection with other machine learning approaches,the machine learning approaches are not the same as the ATFC 3100mechanisms. For example, machine learning engines may useclustering/batch processing and frames, or pseudo real time and offlineprocessing to carry out its learning with, for example, unscented Kalmanfilters to develop new rules and adapt in real time as opposed to theapproach used in the ATFC 3100. But it should be recognized that theATFC 3100 may be used in parallel with machine learning engines.

In addition, the ATFC 3100 is particularly applicable to multiple inputmultiple output (MIMO) nonlinear, chaotic, and uncertain plasma loads,that can be unstable as well as have unstable zero dynamics. Asdescribed further herein, in addition to adaptation of the input andoutput membership functions (of the fuzzification module 3104 anddefuzzification module 3108, respectively) and adaptation of the rulebase 3110, the dynamic modification module 3112 may also store updatesto the rule base 3110 and expand the rule base 3110 through tensorialcorrection values, zooming and sliding tensorial memory grids, anddelay/filtering/averaging operators. Moreover, the dynamic modificationmodule 3112 may also genericize the rule base 3110, the input and outputmembership functions, input and output gain, scaling, and tuning.

Before detailing functional aspects of the dynamic modification module3112, it is helpful to understand the operation of the fuzzy controller3102 by way of an example, without loss of generality. In the plasmaprocessing systems 100, 400, there may be many inputs and outputs (e.g.,rail voltage, drive voltage, generator frequency, match settings, etc.)but taking a MIMO subset as an example, such as rail voltage and drivevoltage, provides ease of comprehension. For example, the rule base mayinclude the following rules:

-   -   R1: IF (Drive is Reference) AND (Error is positive) THEN (Rail        is Up);    -   R2: IF (Drive is Reference) AND (Error is zero) THEN (Rail is        zero);    -   . . .    -   Rn: IF (Ini is Conditioni) AND (Ink is Conditionm) THEN (Outputp        is Conditionp).

Again, the ATFC 3100 is a MIMO system capable of effectuating rules thatwill not only generate a rail voltage, but may also, for example,establish drive frequency, substrate-bias voltage, and match positionsfor all amplifiers and match networks. As a consequence, the rule base3110 is composed of all the “Rn” rules for all the i inputs, all theconditions, and all the outputs.

The fuzzification module 3104 functions to create a “degree of truth” toeach statement by mapping how much “Drive is Reference” and how much“Error is Positive” and how much “Error is Zero,” which is achievedthrough the membership functions, MFin, as is known in the art. Due toavailable processing devices (e.g., CPUs and FPGAs) and to make storagecomputations easy, the shape of the membership functions (in a generic,normalized form) may be as shown in FIG. 33 . As shown in FIG. 33 , themembership functions may be composed of 2n points with points “pi” and“ri” spaced from a center “bo” in a symmetric manner about bo.

In the ATFC 3100, adaptation is carried out on {bo, pi, . . . pn, ri, .. . , rn} for all MFin functions. Pn and rn may overlap; thus, makingthe membership function triangular about bo. It should be noted that thedistance between bo and pi and bo and ri does not need to be smallerthan “bo and pi−1” and “bo and ri.” Only the symmetry of “pi” and “ri”with respect to “bo” is desired, and pi should lie to the left of bo andri, should lie to the right of bo and pi.

The number of points “n” may be selected based on the hardware. Applyingthe above definitions to this example and without loss of generality,everything may be normalized between [−1, 1], or alternatively, between[0, 1]. Assuming (as an example only) Reference equals 0.85, Drive=0.85,and Error is 0.1, then the membership functions are depicted in FIG. 34.

Using “Up” as “Positive” for the rail, “Down” as “Negative,” and “Drive”as “Reference” correlated to “(Reference-Drive)==0” it can be seen thatthere are two laws activated per rule. FIG. 35 depicts Rule 1 (R1) andFIG. 36 depicts Rule 2 (R2).

As a consequence, the fuzzyification mechanism will output:

-   -   Rin=1 AND 0.3    -   R2in=1 AND 0.7.

Depending upon how the “AND” operator is defined, R1in and R2in willtake on the corresponding values. For the present example, since theminimum operator is faster and less resource intensive, especially fortensors, as compared to other operations such as multiplication, thefuzzification module A04 will send to the inference mechanism A06 thefollowing:

R1in = min (1, 0.3) = 0.3 R2inin = min (1, 0.7) = 0.7 R3in = 0 …Rnin = 0.

In turn, the inference mechanism 3106 simply reads these rule values andcomputes the output membership function resulting from them. As aconsequence, we have the membership function depicted in FIG. 37 forR1in and the membership function depicted in FIG. 38 for R2in. Dependingon the way the inference mechanism A06 is implemented, the rule base3110 can have its fuzzy output inferred differently depending on themembership functions used. The defuzzification module A08 then convertsthe inferred decisions into actions. There exist several methods fordefuzzification such as center of gravity, center average, scaling, etc.

By way of example only, the center average may be calculated as:

$\begin{matrix}{\upsilon_{rail} = \frac{{R_{1{out}} \times R_{1{in}}} + {R_{2{out}} \times R_{2{in}}}}{R_{1{in}} + R_{2{in}}}} \\{= \frac{{0.3 \times 1} + {0.7 \times 0}}{0.3 + 0.7}}\end{matrix}$ υ_(rail) = 0.3

As another example, scaling is calculated as:

$\begin{matrix}{\upsilon_{rail} = \frac{{1 \times \left( \frac{0.\overset{\_}{6} \times 0.3}{2} \right)} + {0 \times \left( \frac{0.\overset{\_}{6} \times 0.7}{2} \right)}}{\left( \frac{0.\overset{\_}{6} \times 0.3}{2} \right) + \left( \frac{0.\overset{\_}{6} \times 0.7}{2} \right)}} \\{= \frac{0.1 + 0}{\left( {3/30} \right) + \left( {7/30} \right)}}\end{matrix}$ υ_(rail) = 0.3

And the center of gravity defuzzification approach may be calculated as:

$\begin{matrix}{\upsilon_{rail} = \frac{{0.\overset{\_}{3} \times \left\lbrack {0.\overset{\_}{6} \times \left( {0.3 - \frac{0.3^{2}}{2}} \right)} \right\rbrack} + {0 \times \left\lbrack {0.\overset{\_}{6} \times \left( {0.7 - \frac{0.7^{2}}{2}} \right)} \right\rbrack}}{0.\overset{\_}{6} \times \left\lbrack {\left( {0.3 - \frac{0.3^{2}}{2}} \right) + \left( {0.7 - \frac{0.7^{2}}{2}} \right)} \right\rbrack}} \\{= \frac{{0.\overset{\_}{3} \times \left( {17/100} \right)} + {0 \times \left( {91/100} \right)}}{\left( {17/100} \right) + \left( {91/100} \right)}}\end{matrix}$ υ_(rail) = 0.1197

Having gone over the concepts, definitions and a practical example, anexample ATFC 3900, which may be used to realize the ATFC 3100 isdescribed with reference to FIG. 39 . As shown, the ATFC 3900 comprisesa fuzzy controller 3902 and a dynamic modification module 3912. Asshown, in implementations where the ATFC 3900 is realized as a controllaw module 506 among other control law modules 506 (such as is shown inFIGS. 5A, 5B, and 5C), the fuzzy controller 3902 receives the control,u_(out), from the selector module 508; the measured system output,y_(meas); the total estimated system output, y_(est_out), and thereference signal, r, while the dynamic modification module 3912 receivesthe measured system output, y_(meas), and the reference signal, r.

The fuzzy controller 3902 operates in the same way as the fuzzycontroller 3102 described with reference to FIG. 31 except that thefunctions of the fuzzification module 3104 are separated into a fuzzyinput scaler module 3920 and a fuzzifier 3922, and functions of thedefuzzification module 3108 are separated into a defuzzifier 3924 and afuzzy output scaler module 3926. As shown, the fuzzy input scaler module3920 receives the measured system output, y_(meas), the total estimatedsystem output, y_(est_out), the control, u_(out), and the referencesignal, r, and the fuzzy output scaler module 3926 outputs u_(desired),which may be processed by the NL transfer functions 1013 to produce thepossible control signal, u_(se). The fuzzy input scaler module 3920 maynormalize the inputs it receives to values between [−1,1] (oralternatively, between [0,1]), and the fuzzy output scaler may providesignal values that are useful for a particular actuator. In someimplementations, the fuzzifier 3922, inference mechanism 3106, and thedefuzzifier 3924 are realized by an FPGA that is programmed usinginstructions in hardware description language and the other componentsdepicted in FIG. 39 are realized by processor executable instructions inconnection with a processor (e.g., CPU) that processes the instructions.

The dynamic modification module 3912 in this embodiment comprises acontrol-to-estimate mapping module 3928, a correction module 3930, ascaling module 3932, a zooming and shifting module 3934, and a memorygrid 3936, that is coupled to the zooming and shifting module 3934 via aone-sample delay, 1SD. In some implementations, these functionalcomponents of the dynamic modification module are realized by softwareexecuted by a processor (e.g., a CPU).

The control-to-estimate mapping module 3928 generally functions toprovide a fuzzy tensorial mapping from the control, u_(out), to theestimated system output, y_(est_se). The estimate may be updated atevery control sample and is adapted to match the measurements, y_(meas).The estimated system output, y_(est_se) may be provided to the selectormodule 508 and the estimation law module 504 as shown in FIGS. 5A and5B.

Referring briefly to FIG. 40 , shown is an embodiment of thecontrol-to-estimate mapping module 3928. As shown, thecontrol-to-estimate mapping module 3928 includes a fuzzy input scalermodule 4050, a fuzzifier 4052, an inference mechanism 4054 that iscoupled to a rule base 4056, a defuzzifier 4058, and a fuzzy outputscaler module 4060. As shown, the fuzzy input scaler module 4050receives the total estimated system output, y_(est_out), the control,u_(out), and the measurements, y_(meas). In operation, thecontrol-to-estimate mapping module 3928 provides a fuzzy estimate,y_(est_se), of the controlled output of the system (obtained throughdefuzzification) and the calculation for y_(est_se) is adapted in realtime by having its defuzzification coefficients adapted in real time bythe estimated model parameter tensor, Θ, to minimize the error betweeny_(estk_1) which are given by θ_(k) every iteration.

The correction module 3930 functions to provide a tensorial mapping fromthe measurements, y_(meas), relative to the reference signal, r, (e.g.,streaming setpoints) into a correction tensor, CT, added to theinput/output membership function centers and points. As such, thecorrection module 3930 enables an adaptation at each and every controlsample to minimize an error between the measurement and the referencesignal.

Referring briefly to FIG. 41 , shown is an embodiment of the correctionmodule 3930. As shown, the correction module 3930 includes a fuzzy inputscaler module 4170, a fuzzifier 4172, an inference mechanism 4174 thatis coupled to a rule base 4176, a defuzzifier 4178, and a fuzzy outputscaler module 4180. As shown, the fuzzy input scaler module 4170receives the control, u_(out), the total estimated system output,y_(est_out), the reference signal, r, the measurements, y_(meas), andestimated system output, y_(est_se). As depicted, the estimated modelparameter tensor, Θ, is utilized by each of the fuzzifier 4172 and thedefuzzifier 4178 to different effect. Specifically, Θ is utilized toaffect the coefficients of the input membership functions (MFin) of thefuzzifier 4172 so as to affect the fuzzy values output by the fuzzifier4172. And the estimated model parameter tensor, Θ is also utilized toaffect the coefficients of the defuzzifier 4178 to, e.g., enablemodification of the weights used with the center of gravity method.

As shown, the correction module 3930 produces a correction tensor, CT.In general, the correction tensor, CT, is indicative of an error, and itis generally desirable to minimize the correction, so as a consequence,parameters are adjusted so the CT tends to move to zero.

In addition to this correction tensor, CT, the meaning of the rules maybe adjusted by scaling them with the scaling module 3932. As such, thescalars may autotune themselves so they narrow or extend the inputs sothat the normalized range covers these inputs and not a larger inregion. The inputs and scaling are considered over timeframes andcalculated based upon the reference signal, r, which may be organizedinto synthesized frames.

The zooming and shifting module 3934 functions to shift the rule setwith respect to a fixed grid such that updates are made only inside theactive rules and membership functions. So, in other words, the entirerule base is zoomed in to cover only the active rules and shiftedoutside the original definitions whenever the rules that are active(e.g., corresponding to different operating conditions) are beyond theinitial definitions. The power of this zooming-shifting method istwofold: first, because the scaling module 3932 changes the whole rulebase meaning, this zooming-shifting method only zooms into the activerules; thus, only affecting the current active rules. Second, thismethod allows extending the rule base to a different set of conditions(inputs/outputs). So, using the estimated model parameter tensor, Θ, thezooming and shifting module 3934 optimizes itself and selects theshifting method to cover solely the current active laws.

Referring to FIG. 42 , shown is an embodiment of the zooming andshifting module 3934, which includes an active region module 4290,boundary logic 4292, shift-zoom logic 4294, a multiplexor 4296, and arules selection module 4298. The active region module 4290 is configuredto divide operational aspects of the system into regions utilizing themeasured system output, y_(meas), the reference, r, the total estimatedsystem output, y_(est_out) and the control, u_(out), to determine whichregion is currently active.

In turn, the boundary logic 4292 provides a TRUE signal if the activeregion is outside of the current active rule set and a FALSE signal ifthe active region is not outside of the active rule set boundaries. Inresponse to the TRUE signal (indicating the active region is outside ofthe current active rule set), the shift-zoom logic 4294 will shift thecenter of the rules. The active region is a region of the rule basearound the rules that are currently non-zero. The center of the regionis where the measurements lead to a highest rule membership value (e.g.,the rule the measurements/inputs fit into by the greatest amount).

In response to a FALSE signal, the shift-zoom logic 4294 will zoom in soas to cover the rules that are available so far. As shown, theshift-zoom logic 4294 receives the estimated model parameter tensor, Θ,and based upon Θ establishes the amount by which the rule base should beshifted or zoomed into so as to only require one active rule boundaryset (e.g., for a single frame period).

The multiplexor 4296 then passes along either the shifted or thezoomed-in value based upon a shift/zoom signal. The rule selectionmodule 4298 then determines a new tensor correction, TCnew, that enablesa shift in the rules (relative to TC), so that instead of applying TC toall the rules in the system, TCnew is applied to a subset of rules fromthe rule base. In this way, only a subset of the rules (e.g., the ruleswhere the system has been the last few samples) are moved.

As shown, CTnew is fed to the fuzzifier 3922, the rule base 3110, andthe defuzzifier 3924. CTnew enables the zooming and shifting (performedby the zooming and shifting module 3934) to be applied to the fuzzifier3922, defuzzifier 3924, and the rule base 3110 to enable the membershiprules (of the fuzzifier 3922 and defuzzifier 3924) and rule base 3110 tobe changed. For example, a center of the membership rules (e.g., bodepicted in FIG. 33 ) may be changed. Without the application of thezooming and shifting, the entire rule base 3110 would be changed. But ifoperation is within a linear system, it is desirable to shift the rulebase 3110 around the current region where the system is operating, sothe zooming and shifting allows a change to the correction factor, TC,based on the measurements that have been obtained in the region thesystem has been currently operating. In the context of the rule base3110, application of the new tensor correction, TCnew results inadjustment of the rules where they are needed (e.g., based on themeasurements). Instead of having a coarse mesh, it is desirable to havethe rule base 3110 be very fine within the region of operation.

The memory grid 3936 creates a memory tensor composed of a grid thatstores the new correction tensor, CTnew, for all the active laws duringa period of time (e.g., during a frame). As such, a next time the sameconditions are experienced, the new correction tensor, CTnew, isavailable and performance (e.g., robustness and reliability) willneither degrade nor change and adaptation need not be restarted.

If the memory grid 3936 requires more resources than are available,instead of using and storing the entire new correction tensor, anadaptation procedure may be used to determine an equivalent correctiontensor that (given the amount of memory locations determined fromhardware limitations or designed specs) is used for all the rules in aset of coarse memory locations such that it minimizes output error. Inthis way, an equivalent correction tensor may be adapted based upon thenew correction tensor that is used during a frames' length for the mosttime (e.g., weights of the average may be selected such that r minusy_(est_out) tends as close as possible to zero where the

$\left. {{{equivalent}{current}{tensor}} = {= {{\sum}_{i = 1}^{n}\frac{\theta_{i}{CT}_{{new}_{i}}}{1}}}} \right).$

Where n is the size of memory cell in terms of the actual rule set(number of fine cells in a coarse cell) and Θ is the estimated modelparameter tensor.

When the ATFC is implemented as a standalone controller, the estimationlaw modules/FELB can be replaced by an empirically derived lookup tablefor the estimated model parameter tensors, Θ. More specifically, alookup table can be empirically formed as a mapping between (1) y_(meas)and u_(out) from a reference/calibration system and (2) estimated modelparameter tensors, Θ. During operation of the ATFC standalonecontroller, the control, u_(out), can be provided to the controlling theone or more actuators 408, and measurements, y_(meas), can be taken fromthe one or more actuators and/or system. These can then be used toselect estimated model parameter tensors, Θ, from the lookup table, andthen provided to the ATFC standalone controller to determine the controlsignal, u_(out). This control signal, u_(out), can be provided to theone or more actuators. Alternatively, the ATFC standalone controller canproduce a string of possible control signals, u_(se), and form thecontrol, u_(out), as a combination of the string. For instance, aweighted average of the possible control signals, u_(se), can be used tocalculate the control, u_(out), although other methods of combining thestring can also be implemented. In some embodiments, the combination maybe based on estimated system outputs, y_(est_se), for each of thepossible control signals, u_(se), similar to the way in which a topologyis selected in the selector and combiner mentioned earlier. Theseestimated system outputs, y_(est_se), can be found via an estimationportion of the nonlinear model, for instance, using Model 1:

y _(est_se) =W _(m) {u _(se),Θ}

Where the estimated model parameter tensor, Θ, is found in the lookuptable based on the measured system output, y_(meas), and the control,u_(out), both from a previous iteration.

Adaptive Engine with Pre-Processed Control Laws

As previously noted, the control law modules or sub-engines can beprocessed on an FPGA or similar high-speed resource. However, for legacysystems that do not have such a resource, legacy processing may havedifficulty implementing the heretofore mentioned control laws. Onepossible solution considered was application of gainscheduling-linearizing the system offline and then finding a controllercapable of controlling the linearized system for various controls.However, any small parameters changes lead to a failure of this controlapproach. Another considered solution was to implement a robustcontroller, but this still led to poor performance, a small region ofuseful operation, and a lack of repeatability. Yet another proposallooked at interpolating between different controllers tailored todifferent operating regimes and challenges, yet while this was found tobe effective for linear systems, it was found to be ineffective fornonlinear systems such as plasmas.

Eventually, the inventor conceived of developing a series of mappingsbetween empirical data and controls that could be used as a replacementfor the control law functionality. Certainly some convergence speed andlatency are sacrificed over the adaptive engine as previously discussed,but this solution does prove effective given hardware limitations seenin many legacy power systems.

FIG. 49 illustrates a method of adaptive control where mappings of thecontrol laws are empirically derived. The method 4900 starts by settingone or more actuators controlling a power system to 0 (Block 4902) inwhat will be called a boot up phase of the adaptive controller. A systemoutput measurement, y_(meas), is taken for the system controlled by theone or more actuators (Block 4903), and this measurement is input to amapping function (Block 4904) to get a possible control, u_(se), thatcorresponds to the measurement, y_(meas). The mapping function can berelated to and approximate the effects of a nonlinear model throughempirical study of the power system. This possible control signal,u_(se), is provided to the one or more actuators (Block 4906), and islikely zero or below a zero threshold at least for a first fewiterations of the boot up phase (Decision 4908=No). If this version ofthe adaptive engine includes a single possible control signal, u_(se),then u_(se)=u_(out), or where multiple possible control signals, u_(se),are provided from separate mapping functions, then the b_(est) u_(se) ora combines u_(se) can be the u_(out). Another system output measurement,y_(meas), is taken (Block 4903), and again inputted to the mappingfunction (Block 4904), which provides another possible control, u_(se),that corresponds to the second measurement, y_(meas), and that isprovided to the one or more actuators (Block 4906). This portion of theboot up phase (Block 4903-4908) loops until a possible control, u_(se),greater than the zero threshold occurs (Decision 4908=Yes), at whichpoint the adaptive engine has reached an end of the boot up phase.

Adaptation can now begin following similar steps to those seen inearlier descriptions (e.g., see similarities between Adaptation phaseand FIG. 7 ). Control samples can be grouped into frames and a bestlinear approximation of the system behavior over the new frame can beselected (Block 4910)—in other words, a structure of a time-varyinglinear system, W_(m), can be selected for the first frame (Block 4910).This structure can be calculated in a frame resynthesizer or accessedfrom an empirically-derived lookup table. Another system outputmeasurement, y_(meas), can be taken (Block 4912), but this time themeasurement can be used in an estimation law module as previouslydiscussed (Block 4914). In particular the estimation law module canestimate an estimated model parameter tensor, Θ, for every controlsample of a nonlinear model, where this estimation is at least afunction of the system output measurement, y_(meas), and an inputregressor, Ø. The input regressor, Ø, for this first iteration of theAdaptation phase may include a reference signal, r, and the last controlfrom the boot up phase, u_(out). In subsequent iterations, Ø, mayinclude additional components such as y_(est_se). The estimating can bebased on an estimation law that is a function of an estimated error, ê,or cost function, J. The estimated model parameter tensor, Θ, comprisesestimated parameters of the nonlinear model such as, but not limited to,r, y_(meas), y_(est_se), and u_(out). These Θ values can be elementswithin the A, B, and C matrices of a system of equations underlying thetime-varying linear system, W_(m), which is used in the nonlinear model,and in particular, in an estimation portion of the nonlinear model. Theestimated model parameter tensor, Θ, can be input to the mappingfunction used in the boot up phase, and via a different mapping in themapping function, a possible control signal, u_(se) can be extractedfrom the mapping function based on the Θ input (Block 4916). In otherwords, the mapping function can have two operations or two sets ofmappings: (1) a first that gives u_(se) in terms of y_(meas), and (2) asecond that gives u_(se) in terms of Θ. The adaptive engine can thenprovide the possible control signal, u_(se), to an estimation portion ofthe nonlinear model to generate an estimated system output, y_(est_se)(Block 4918) estimated to result if the possible control signal, u_(se),is provided to the one or more actuators. The estimation portion of thenonlinear model uses the structure for the time-varying linear system,W_(m), selected for the current frame with u_(se) and Θ as inputs.Alternatively, an additional realm of the mapping function can give theestimated system output, y_(est_se), based on an input of the possiblecontrol signal, u_(se) (Block 5018 in FIG. 50 ). If used, the estimationportion of the nonlinear model is also a function of the estimated modelparameter tensor, Θ. In some embodiments, the estimation portion of thenonlinear model can be implemented in the estimation law module, thoughthis processing location is not limiting.

The mapping function can also provide the possible control signal,u_(se), to the one or more actuators (Block 4920) as the control,u_(out), assuming no other possible control signals, u_(se), for thiscontrol sample or iteration, are provided by the mapping function oranother mapping function. If another possible control signal, u_(se), isprovided (this variation is not shown, but will be familiar fromprevious discussions of the adaptive engine), the method 4900 can select(1) a b_(est) possible control signal, u_(se), from a set including thepossible control signal, u_(se), from the first mapping function, andadditional possible control signals, u_(se), or (2) a b_(est)combination of possible control signals, u_(se), blended from two ormore of the set. The blending can be based on a topology that caninclude averaging, multiplication, summations, differences, divisions,integrals, derivatives, exponentials, complex functions, logarithms,series, statistical distributions, matrices, tensors, neural networks,nonlinear functions, graphs, maps, transformations, trees, to name a fewnon-limiting examples, or combinations thereof. The topology can beselected based on a total estimated system output, y_(est_out), for eachof multiple possible topologies, and then based on comparing this totalestimated system output, y_(est_out), to the reference signal, r, themeasured system output, y_(meas), or a combination of these (referred toas estimated system error, ê_(out)). For instance, a specific exampleusing all three of these values is shown in Equation 4, where a costfunction, J_(out) of two errors is used. This selection and/or blendingcan be performed by a selector module, such as the selector modules 508.

If the current frame has not ended (Decision 4922=No), then theadaptation of the estimated model parameter tensor, Θ, (Blocks4912-4922) repeat for all iterations or control samples in the frame(until Decision 4922=Yes). This adaptation leaves the linearapproximation (or structure of the time-varying linear system, W_(m))constant through the frame, but adapts the estimated model parametertensor, Θ, at each control sample or iteration in the frame until thebifurcated nonlinear model converges on the system's nonlinear behavior.

At the end of each frame (Decision 4922=Yes), a new linear approximation(structure of the time-varying linear system, W_(m)) is calculated oraccessed (Block 4910), and adaptation of the estimated model parametertensor, Θ, again restarts from the baseline of the linear approximationuntil convergence on the nonlinear system behavior is achieved. Thefinal estimated model parameter tensor, Θ, in each frame can be storedalong with a mapping to the frame and the structure of the time-varyinglinear system, W_(m), such that these values can be recalled should thereference signal, r, underlying the frame be seen again.

As seen, this alternative adaptive engine operates similarly to thoseshown in previous aspects of this disclosure, but with a unique boot upphase and unique u_(se) of a mapping function rather than the controllaw module to determine the possible control signal, u_(se), from theestimated model parameter tensor, Θ. Further, FIG. 50 shows anotheralternative where the mapping function also determines the estimatedsystem output, y_(est_se) based at least on the possible control signal,u_(se), also found from the mapping function.

In the above description the possible control signal, u_(se), iseffectively the control, u_(out), previously discussed, since it isprovided directly to the actuators. However, in other embodiments, theadaptive engine can include multiple estimation law modules eachproducing their own estimated model parameter tensors, Θ, that can allbe fed into the mapping function to produce different possible controlsignals, u_(se), and then a selector module can select a best of thesepossible control signals, u_(se), or a best combination or blending oftwo or more of these possible control signals, u_(se), as the control,u_(out). In another alternative, multiple estimation law modules canfeed multiple mapping functions, each mapping function approximatingdifferent ones of the control laws discussed previously, and again, aselector module can select a one or combination of possible controlsignals, u_(se), as the control, u_(out). Where multiple possiblecontrol signals, u_(se), come into play, the estimated system outputs,y_(est_se), corresponding to each of these, can be used in the selectormodule to select the one or a combination of the possible controlsignals, u_(se), as the control, u_(out).

The estimation law module can use any number of estimation laws, suchas, but not limited to, Estimation Laws 1-7 previously discussed, thoughthey typically are a function of the estimation error, ê, which can bebased on a difference between two or more of r, y_(meas), andy_(est_se). The estimation laws are also typically a function of theinput regressor, Ø. Some estimation laws may include an adaptation gain,that controls an influence that adaptation has on the control, u_(out).

Where a single estimation law module and a single mapping function areused, and rather than apply u_(se) as the u_(out), a string of multipleu_(se) can be combined, for instance in an average, to produce a controlu_(out) at each control sample or iteration.

FIGS. 51-53 illustrate components of an adaptive engine implementing amapping function to enable the adaptive engine to operate on legacyhardware that may have limited processing resources. For instance, wherethe FPGA previously discussed as processing the control laws (or controlportion of the nonlinear model) is not available or has insufficientprocessing power to perform these functions, FIGS. 51-53 may provide astrong alternative. For instance, FIG. 50 illustrates the mappingfunction 5002A as used during the boot up phase discussed relative toFIGS. 49 and 50 . In particular, the mapping function 5002A can providea possible control signal, u_(se), based on a system output measurementof the one or more actuators or a power system controlled by the one ormore actuators. This means of generating the possible control signal,u_(se), which may be provided to the one or more actuators as thecontrol, u_(out), can be repeated until the possible control signal,u_(se), exceeds a zero threshold. The mapping function 5002A can berelated to a nonlinear model via an empirical study of the power system.A separate region of the mapping function 5002B can then operate as partof a larger adaptive engine as shown in FIG. 52 or 53 . Alternatively,the mapping function 5002B shown in FIGS. 52 and 53 can be a distinctmapping function from the one shown in FIG. 51 . The mapping functions5002B and 5002C can also be related to the nonlinear model via anempirical study of the power system. As seen, these two regions of themapping function or distinct mapping functions have distinct operation:the first provides u_(se) in terms of y_(meas) and the second providesu_(se) in terms of Θ. Where the possible control signal, u_(se), isprovided directly to the one or more actuators, or combined in a stringof possible control signals, u_(se), from the mapping function 5002B,the estimation portion 808 may not be needed. The estimation portion 808produces the estimated system output, y_(est_se), corresponding to eachpossible control signal, u_(se), and this output has two functions: (1)to help a selector module in selecting a best or a best combination ofpossible control signals, u_(se), as the control, u_(out); and (2) toaid in calculating an estimation error, ê. However, where a selectormodule is not needed because the possible control signal, u_(se), isprovided directly to the one or more actuators, and where the estimationerror, ê, is found using a form that does not use y_(est_se) (e.g.,instead using |y_(meas)−r|), then the estimation portion 808 may besuperfluous and can be excluded. Similarly, the mapping function 5002Cin FIG. 53 can also be optional for these same reasons.

Aside from the mapping function 5002B, FIG. 52 operates as described inFIG. 8A, and thus reference can be made to that figure and thecorresponding description for an appreciation of the remainder of FIG.52 . The alternative shown in FIG. 53 is also very similar to FIG. 8A,but here replaces the estimation portion 808 of the nonlinear model withan additional region of the mapping function 5002C (or a distinctmapping function). This mapping function 5002C provides an estimatedsystem output, y_(est_se), corresponding to a possible control signal,u_(se), based on inputs that include the estimated model parametertensor, Θ, the structure of the time-varying linear system, W_(m), andoptionally the input regressor, Ø. The specific inputs used depend onthe form of the nonlinear model being used.

Although FIGS. 51-53 do not u_(se) a control law module, the mappingfunction 5002A, 5002B, and optionally 5002C can still be developed toimplement a control law. In fact, the mapping functions 5002A, 5002B,and optionally 5002C can produce virtually the same possible controlsignals, u_(se), as the control law modules or sub-engines describedearlier in this disclosure, including the TLMC, TARC, L1, Adaptive PID,ATIMC, and ATFC. Admittedly, speed and other parameters will besacrificed by implementing the control laws in the mapping functions ascompared to the control law modules previously described. However, wherehardware is limiting, the solutions provided in FIGS. 49-53 stillprovide a worthy improvement over existing adaptive controllers.

The methods described in connection with the embodiments disclosedherein may be embodied directly in hardware, in processor-executablecode encoded in a non-transitory tangible processor readable storagemedium, or in a combination of the two. Referring to FIG. 48 forexample, shown is a block diagram depicting physical components that maybe utilized to realize the adaptive engine according to an exemplaryembodiment. As shown, in this embodiment a display portion 4812 andnonvolatile memory 4820 are coupled to a bus 4822 that is also coupledto random access memory (“RAM”) 4824, a processing portion (whichincludes N processing components) 4826, an optional field programmablegate array (FPGA) 4827, and a transceiver component 4828 that includes Ntransceivers. Although the components depicted in FIG. 48 representphysical components, FIG. 48 is not intended to be a detailed hardwarediagram; thus many of the components depicted in FIG. 48 may be realizedby common constructs or distributed among additional physicalcomponents. Moreover, it is contemplated that other existing andyet-to-be developed physical components and architectures may beutilized to implement the functional components described with referenceto FIG. 48 . For instance, while the RAM 4824 may take the form of aTSP-RAM in some instances, other forms of RAM can also be implemented.Further, while the frame resynthesizer may be implemented in theprocessing portion 4826 (e.g., a CPU) due to hardware limitations intoday's FPGAs, future FPGAs or similar-type resources may be able toperform both the functions of the frame resynthesizer, estimation lawmodules, control law modules, selector module, and the control andestimation portions of the nonlinear model. For instance, future neuralnetworks or quantum computing may enable a neural-network enabledprocessor or quantum computer to perform all processes of the adaptiveengine without splitting functionality between different processingresources. With existing hardware, the processing portion 4826 is likelyto process frames and the structure of the time-varying linear system,W_(m), and possibly the estimated model parameter tensor, Θ, while theFPGA 4827 is like to process the control law modules, the control andestimation portions of the nonlinear model, and the selector module (andin some cases may take on estimation of the estimated model parametertensor, Θ, too).

This display portion 4812 generally operates to provide a user interfacefor a user, and in several implementations, the display is realized by atouchscreen display. In general, the nonvolatile memory 4820 isnon-transitory memory that functions to store (e.g., persistently store)data and processor-executable code (including executable code that isassociated with effectuating the methods described herein). In someembodiments for example, the nonvolatile memory 4820 includes bootloadercode, operating system code, file system code, and non-transitoryprocessor-executable code to facilitate the execution of methodsdescribed with reference to FIGS. 7, 9, 32, 47, and 49 described furtherherein. For instance, the non-transitory processor-executable code couldfacilitate execution of steps used to carry out adaptation of thenonlinear model including steps for identifying frames, selecting astructure of W_(m) at each frame, and adapting Θ at each control sampleto produce a control u_(out) that is tailored to specific operatingregimes and instability challenges.

In many implementations, the nonvolatile memory 4820 is realized byflash memory (e.g., NAND or ONENAND memory), but it is contemplated thatother memory types may be utilized as well. Although it may be possibleto execute the code from the nonvolatile memory 4820, the executablecode in the nonvolatile memory is typically loaded into RAM 4824 andexecuted by one or more of the N processing components in the processingportion 4826.

The N processing components in connection with RAM 4824 generallyoperate to execute the instructions stored in nonvolatile memory 4820 toenable adaptation. For example, non-transitory, processor-executablecode to effectuate the methods described with reference to FIGS. 7, 9,32, 47, and 49 may be persistently stored in nonvolatile memory 4820 andexecuted by the N processing components in connection with RAM 4824. Asone of ordinarily skill in the art will appreciate, the processingportion 4826 may include a video processor, digital signal processor(DSP), micro-controller, graphics processing unit (GPU), or otherhardware processing components or combinations of hardware and softwareprocessing components (e.g., an FPGA or an FPGA including digital logicprocessing portions).

In addition, or in the alternative, the processing portion 4826 may beconfigured to effectuate one or more aspects of the methodologiesdescribed herein (e.g., the methods described with reference to FIGS. 7,9, 32, 47, and 49 ). For example, non-transitory processor-readableinstructions may be stored in the nonvolatile memory 4820 or in RAM 4824and when executed on the processing portion 4826, cause the processingportion 4826 to perform adaptation using a bifurcated nonlinear model.Alternatively, non-transitory FPGA-configuration-instructions may bepersistently stored in nonvolatile memory 4820 and accessed by theprocessing portion 4826 (e.g., during boot up) to configure thehardware-configurable portions of the processing portion 4826 toeffectuate the functions of the adaptive engine.

The input component 4830 operates to receive signals (e.g., thereference signal, r) that are indicative of one or more aspects of adesired waveform or desired performance of the power system. The signalsreceived at the input component may include, for example, setpoints orpower delivery parameters or a plasma processing recipe. The outputcomponent generally operates to provide one or more analog or digitalsignals to effectuate an operational aspect of the adaptive engine. Forexample, the output portion 4832 may provide the control, u_(out), tothe one or more actuators.

The depicted transceiver component 4828 includes N transceiver chains,which may be used for communicating with external devices via wirelessor wireline networks. Each of the N transceiver chains may represent atransceiver associated with a particular communication scheme (e.g.,WiFi, Ethernet, Profibus, etc.).

Some portions are presented in terms of algorithms or symbolicrepresentations of operations on data bits or binary digital signalsstored within a computing system memory, such as a computer memory.These algorithmic descriptions or representations are examples oftechniques used by those of ordinary skill in the data processing artsto convey the substance of their work to others skilled in the art. Analgorithm is a self-consistent sequence of operations or similarprocessing leading to a desired result. In this context, operations orprocessing involves physical manipulation of physical quantities.Typically, although not necessarily, such quantities may take the formof electrical or magnetic signals capable of being stored, transferred,combined, compared or otherwise manipulated. It has proven convenient attimes, principally for reasons of common usage, to refer to such signalsas bits, data, values, elements, symbols, characters, terms, numbers,numerals or the like. It should be understood, however, that all ofthese and similar terms are to be associated with appropriate physicalquantities and are merely convenient labels. Unless specifically statedotherwise, it is appreciated that throughout this specificationdiscussions utilizing terms such as “processing,” “computing,”“calculating,” “determining,” and “identifying” or the like refer toactions or processes of a computing device, such as one or morecomputers or a similar electronic computing device or devices, thatmanipulate or transform data represented as physical electronic ormagnetic quantities within memories, registers, or other informationstorage devices, transmission devices, or display devices of thecomputing platform.

The terms and expressions employed herein are used as terms andexpressions of description and not of limitation, and there is nointention, in the use of such terms and expressions, of excluding anyequivalents of the features shown and described or portions thereof.Each of the various elements disclosed herein may be achieved in avariety of manners. This disclosure should be understood to encompasseach such variation, be it a variation of an embodiment of any apparatusembodiment, a method or process embodiment, or even merely a variationof any element of these. Particularly, it should be understood that thewords for each element may be expressed by equivalent apparatus terms ormethod terms-even if only the function or result is the same. Suchequivalent, broader, or even more generic terms should be considered tobe encompassed in the description of each element or action. Such termscan be substituted where desired to make explicit the implicitly broadcoverage to which this invention is entitled.

As but one example, it should be understood that all action may beexpressed as a means for taking that action or as an element whichcauses that action. Similarly, each physical element disclosed should beunderstood to encompass a disclosure of the action which that physicalelement facilitates. Regarding this last aspect, by way of example only,the disclosure of a “protrusion” should be understood to encompassdisclosure of the act of “protruding”-whether explicitly discussed ornot—and, conversely, were there only disclosure of the act of“protruding”, such a disclosure should be understood to encompassdisclosure of a “protrusion”. Such changes and alternative terms are tobe understood to be explicitly included in the description.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

As used herein, the recitation of “at least one of A, B and C” isintended to mean “either A, B, C or any combination of A, B and C.” Theprevious description of the disclosed embodiments is provided to enableany person skilled in the art to make or use the present disclosure.Various modifications to these embodiments will be readily apparent tothose skilled in the art, and the generic principles defined herein maybe applied to other embodiments without departing from the spirit orscope of the disclosure. Thus, the present disclosure is not intended tobe limited to the embodiments shown herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A control system comprising: a user interfaceconfigured to receive a reference signal defining target values for acontrolled parameter that is provided to a controlled output of thesystem; at least one sensor to obtain a measure of the controlledparameter that is controlled at the controlled output; an estimation lawmodule configured to produce an estimated model parameter tensor, Θ afuzzy controller configured to provide a control signal to adjust atleast one actuator based at least upon the reference signal and themeasure of the controlled parameter; a dynamic modification moduleconfigured, while controlling the controlled parameter, based at leastupon the reference signal, an estimate of the controlled parameter, themeasure of the controlled parameter, and the control signal to: adaptoutput membership functions of the fuzzy controller; adapt inputmembership functions of the fuzzy controller; and adapt a rule base ofthe fuzzy controller.
 2. The control system of claim 1 wherein theoutput membership functions, the input membership function and the rulebase are adapted simultaneously during each sample.
 3. The controlsystem of claim 1 wherein the output membership functions, the inputmembership function and the rule base are adapted asynchronously.
 4. Thesystem of claim 1, wherein the controlled output is an output coupled toa plasma processing chamber.
 5. The system of claim 1, wherein thecontrolled output is an output of an actuator within the system.
 6. Thesystem of claim 1, wherein the user interface is configured to at leastone of enable an operator of the system to set the target values andenable a controller to set the target values.
 7. The system of claim 1,wherein the at least one actuator comprises a DC section configured toapply a DC rail voltage to a power amplifier.
 8. The system of claim 1,wherein the parameter that is controlled is one of forward power,reflected power, or reflection coefficient.
 9. A method for controllinga plasma processing system comprising: receiving a reference signaldefining target values for a parameter that is controlled at an outputof the plasma processing system; obtaining a measure of the parameterthat is controlled at the output; producing an estimated model parametertensor, Θ; using a fuzzy controller to provide a control signal toadjust at least one actuator based at least upon the reference signaland the measure of the controlled parameter; adapting output membershipfunctions of the fuzzy controller, input membership functions of thefuzzy controller, and a rule base of the fuzzy controller whilecontrolling the controlled parameter, based at least upon the based atleast upon the estimated model parameter tensor, Θ, the referencesignal, an estimate of the controlled parameter, the measure of thecontrolled parameter, and the control signal.
 10. The method of claim 9,wherein the output is an output coupled to a plasma processing chamber.11. The method of claim 9, wherein adjusting the at least one actuatorcomprises adjusting a DC section configured to apply a DC rail voltageto a power amplifier.
 12. The method of claim 9, wherein the parameterthat is controlled is one of forward power, reflected power, orreflection coefficient.
 13. The method of claim 9, wherein the output isan actuator output of the at least one actuator.
 14. A non-transitorymedium encoded with instructions that are executable by a processorand/or used to program a field programmable gate array, the instructionsincluding instructions to: receive a reference signal defining targetvalues for a parameter that is controlled at an output of a plasmaprocessing system; obtain a measure of the parameter that is controlledat the output; produce an estimated model parameter tensor, Θ; use afuzzy controller to provide a control signal to adjust at least oneactuator based at least upon the reference signal and the measure of thecontrolled parameter; adapt output membership functions of the fuzzycontroller, input membership functions of the fuzzy controller, and arule base of the fuzzy controller while controlling the controlledparameter, based at least upon the based at least upon the estimatedmodel parameter tensor, Θ, the reference signal, an estimate of thecontrolled parameter, the measure of the controlled parameter, and thecontrol signal.
 15. The non-transitory medium of claim 14, wherein theinstructions comprise instructions to provide the control signal to anoutput coupled to a plasma processing chamber.
 16. The non-transitorymedium of claim 14, wherein the instructions to adjust the at least oneactuator comprise instructions to adjust a DC section configured toapply a DC rail voltage to a power amplifier.
 17. The non-transitorymedium of claim 14, wherein the parameter that is controlled is one offorward power, reflected power, or reflection coefficient.
 18. Thenon-transitory medium of claim 14, wherein the output is an actuatoroutput of the at least one actuator.